Most of my experience with Minelabs is the GP series going back over ten years. I just purchased a E-trac and havent put it through all it's paces yet. I'm still learning it. But , I have played with a friends 705. He hunts along side me with my MXT Pro , and the 705 is a very nice machine. only thing I've found so far it doesnt handle the old rusted iron as well as the MXT Pro. But I know the pro machine better . I think with time I could dial in the 705 better. I'm a big fan of multi tones with coin machines. The 705 does a great job.
As far as gold , small / shallow ,I go GMT, sometimes the old Gold Bug original. Larger gold , deeper nasty ground, The GP series machines.
The 705 is probably the best "all around " machine for the price Minelab makes. It's not going to find the smallest stuff out there or the deepest. It's not meant to. It does alot of stuff real good . It's a great multi task machine.
And by the way. That ring is a helluva find ! If you're making finds like that don't let that machine go ! Nice !