As an owner of a 705 and without turning this into a DIS-versus-DAT, I'd put the decision of it as a 705-or-MXT decision more than the MXT.....
why?
My 705 has been really a really awesome machine, and was my first machine. Turn it on, set the auto noise, set the auto ground balance, choose a discim pack, and start swinging. It is deep, nails silver.... but... here's the 'but'.... lol...
I believe that if you are a casual hunter, you'll love the 705. Sturdy, deep, and simple. If after 3 months of obsession with your machine (like me.. a tech head with OCD), you'll want more options, tweeking, settings, maximizing your machine to your surroundings, etc.,. the VX3 really IS more, like the V3i. EX:You have to change the coil to change the frequency on the 705.... the VX3 runs 3 frequencies. Just one example....
I believe the VX3 is more power, that's why I'd compare the 705 to the MXT. And that's just my opinion of comparing equal level machines.
'all around machine' ? you ask? The 705 has coin, jewelry, and prospecting settings. That's 'all around'.... If you know your machine, its settings, setting it to where you are hunting, and what you are looking for, you can find what you want, within reason.
You can fine tune the VX3 for sure! I went out with someone and I had my little Fisher F2 back-up. No real tweaking, BUT I set that machine to run HOT, knew what to look for within all the chatter with the sounds, and was SMOKING my friend and his machine that cost 5X what the F2 cost.... Same spots and I was NAILING coins.... If I had the VX3 and learned it, it would have been scarey!....
American made & quality customer service .... White's has a repuation for it. I put my 705 thru the paces and it got 'used' and never had an issue, but it's kinda like insurance. You hope you don't need it, but are thankful if you do need it and it's there.