Explorers are good machines, as you know. I've owned each of them in the series, plus the E-TRAC. To answer your question as to what you'd lose.... you'd lose ferrous readings on TID. Does that matter to most detectorists? Probably not, if they were willing to admit it, as most of us dig targets based on the conductivity instead of the ferrous reading. And the X-TERRA has a very accurate TID based on conductive numbers. You will gain a detector that has a very forgiving sweep speed. So if you have trouble swinging the SE Pro too quickly, that shouldn't be an issue with the X-705. You'd lose FBS technology (multiple simultaneous frequency detection). But the 705 can be operated at any one of three frequencies, depending on the coil you use. You lose the "no need to ground balance" capability of the Explorer. But then again, the X-TERRA can be operated with Tracking. Better yet, you can offset the Tracking either with a positive or negative ground balance. Or you can set up with automatic ground balance and lock in the setting. I won't go into all the reasons I like the X-TERRA over the Explorer series. But I will tell you that the weight and balance will be a pleasant surprise. If you have any specific "things" you like about your Explorer, let us know and we can address how the X-TERRA may handle those situations. If you're not real familar with the X-TERRA, I'd invite you to read my eBook, Understanding your X-TERRA, which can be downloaded FREE from Minelab's website. HH Randy