I have all three and without hesitation I would choose the E-TRAC over either the V3 or the F75 LTD for the hunting I do in my ground. Let me try an explain my reasons.... but first let me say that what works here may be totally wrong where you live and hunt. I live in NW GA and I like to hunt "hunted out" parks and lawns. I also jump on any site that I may get like a construction site (which is becoming a rare thing) or a wooded campsite or homeplace. The wooded homesite is comparable to any older lawn though. The ground here is red iron bearing clay and the old sites are, of course, infested with cut square nails and an assortment of old and modern trash. The main factor though is the ground... medium to high mineralization. There were numerous iron furnaces in our county before and during the civil war. So..
1: The E-TRAC trumps the other two in handling the mineralized ground. However the V3 can be set up to handle it if you want to take the time to read a bunch of posts and try a bunch of things to figure out whaty works best at a site... it will get it done. I find that 7.5 works best here for depth and for getting a good TID. The F75 LTD can be set up to work too if you can bring yourself to turn things down to the point where you feel you are wasting to potential of the machine... not in every place but in some.
2: Unmasking good targets in heavy iron and trash. The F75LTD and V3 may do it after a good bit of experience and if you set it right but the E-TRAC will perform exceptionally well at this with minimum experience and a few simple settings.... just the relic pattern-auto+3-ferrous/2-tones... The E-TRAC's ability in this area is due to Minelab's straightening of the conductive line of numbers. Even at depth the conductive number is very reliable and if the ferrous number is reasonable and you are getting a good tone and number from even one direction it will be worth digging and many times is something that the other machines just miss unless the user is really tuned in to that machine... the ET is very forgiving to the beginner unless... UNLESS... the user tries to make it be an Explorer. It is NOT an explorer even though it has many similarities. Running the ET with no disc and in ferrous will NOT umask targets as well as it will using a little disc and switching over to Quickmask with no disc will NOT confirm that there is a good target hiding in the iron. What will happen is that the iron will take over, the conductive number may still look good but the ferrous number will rise into the 30s. Any of the three will find masked targets but neither of the other two will approach the ability of the ET in the hands of the casual or inexperienced user... maybe after many, many hours of use they will.
3: TID/VDI ability. The F75 LTD loses the ability to give a good TID over a few inches in my ground. On a sand beach with little or no mineralization this may not be the case... but in most cases I find it to be jumpy. You have to learn what it is telling you with all those jumping numbers and you can learn it. Some of the tone settings are different in their TID response and are more stable, you have to learn which. The F75 LTD is very good at IDing crowncaps.. better than the others IMO. The V3 if set right (you have to set the ground filter and the recovery to match your swing speed, the mineralization, and the trash) will give you a good VDI at depth... as in 10" I can get a good VDI if I have it set right. Also, in my experience the ET and the V3 are more likely to stop me if I pass over a good but deep target. The F75 LTD is less likely to stop me because of two things. One I am hearing a lot more signals with it and two I may be moving a little faster, but not so much with the LTD. With the original F75 faster sweep speed will give a better TID and signal. With the LTD in BP a slower swing will do better... however, still the ET and the V3 are better at alerting me to a good but deep target and are much better than the LTD at giving a good TID/VDI on deeper targets.
Conclusion... I like all three and in the woods or in an ivy bed I would use the LTD because I can run the coil a few inches above the ground in BP and still get the goodies. For everything else i'd choose the E-TRAC first and frankly I was at a construction site last year where the ground was like a plowed field. My friend had the F75. I had a T2, a Tejon, and the E-TRAC. I chose the Tejon because I could move fast with the 5.5" coil and because it hits hard on lead and brass. (This was a site just outside the New Hope battlefield site). I made some finds with the Tejon but after a while I switched to the E-TRAC because I had not had it that long but my confidence in it was high. It didn't miss a beat with the 11" Pro coil and up and down big furrows, moving fast, it was easily finding relics. It is the only Minelab that is better than the Sovereign generally. The Sovereign, moving slowly, may still give a better, more stable TID than any machine made.
They are all three great machines but the ET is easy to learn, there in no ground balance to fiddle with, just noise cancel, set the sensitivity (usually) to auto+3, set some disc pattern (ALWAYS), and then set a few things to your personal preference and you're off... not much to fiddle with on it. If you're after silver set some disc and use conductive/multi or 4 tones. If you're after relics use the relic pattern or a slightly enlargedrelic pattern and use the conductive number, if you're in iron or minerals the ferrous number may run between 8 and 18 give/take.
The F75 LTD in BP is a great machine but you have to learn how to read the bouncing TID numbers on anything slightly deep in trash, iron, or minerals... but it will work for you. You will make exceptional finds with the F75 LTD.
The V3 will mimic the F75 if you set the ground filter and recovery speed right and will, in many places work better in a single frequency than in all three but it just seems such a waste to me... You have to be aware of your filter and recovery and your swing speed... I usually set those things to match my swing speed so that I don't have to be concious of it but it the conditions dictate that I change the filter and recovery delay then I have to keep in mind how fast or slow I am swinging. Then there are all the different choices for tones and all kinds of other settings. I prefer the SEF 8x6 coil or the D2 with the V3. The 5" coil on the LTD is really good and the 11" Pro coil is excellent on the E-TRAC it has a razor edge seperation. I also have and love both the 8x6 and 12x10 SEF coils for the E-TRAC.
So, if you are in neutral soil the LTD may be the best machine going. If you're in minerals or masked targets i'd recommend the ET. If you like to tweak and hunt in all sorts of places maybe the V3 will do it but, as for me... I have had and am having a hard time warming up to the V3. It would be my third choice of the three. The F75 LTD would be my second choice and the E-TRAC would be my first choice without a second thought... i'd never second guess that decision.
Julien