I have tried 3 different Garretts. The Ace 250, the Gtax 550 and the GTP1350. I have not tried the 1500 or 2500 but if they are close to the 1350 in peformance then they are not even in the same league as the Explorer or the E-Trac. Yes the Minelabs are more expensive but worth it to me. I don't know why some people say (try to make others believe) that you have to spend half an hour setting up the minelabs. This is not true. I turn on the E-Trac, hit noise cancel, wait 30 seconds or so and start hunting, thats it. It remembers your last settings when you turn it off. Sure you can play with the settings just like on any detector but you don't have too.
So coming from someone who has used both brands I can tell you the Garretts are good quality built detectors but are just not on the same level as the Minelabs in performance.