I realize that it's all a matter of where you swing your coil, but a good friend in our club purchased a brand new Ace 250 about six months ago. Since then he has found just under $3000 worth of trade tokens from some of the nearby ghost towns.

I don't believe he'll be looking to "upgrade" any time soon.
As for me, I got one just to see what all the hype was about. Oh my goodness, was I ever delighted. It gets almost as much use as my Garrett 2500 and DFX combined. It's light, batteries last forever, depth is good, target ID is good, price is incredible and, for those who haven't experienced it yet, there is absolutely no one like Garrett for standing behind their products.
I bought my Garrett GTI 2500 6 years ago used off eBay (at half what they were selling for new). In that six years, I've had two minor problems fixed, both of which I had created. Each time, the good folks at Garrett fixed it up like new and wouldn't take a penny for their efforts. Now THAT is customer SERVICE!!!
IMHO, the Ace 250 is worth every penny of the $430 that the X-terra 30 costs, but apparently customer satisfaction is more important to Garrett than the almighty dollar.
A Minelab explorer in the hands of someone who knows how to use it is an incredibly powerful machine. This doesn't mean however, that everything that has the Minelab name on it has that same or even similar power.
I really like Andy's idea. Buy the Ace 250 and all the available accessory coils and use the extra $90 you'll have left over from not buying the X-terra to put gas in your car to take you to your favorite detecting hotspots. You won't regret it!