How does the old Everdrive GB compare to these new X3/X5/X7 flavors?
Loading times are much faster, as advertised. I usually only get to play in short spurts, so not minimizing the time spent loading a new game is great.
At first I wasn't sure about having the button that you squeeze in the cart to go back to the menu - I thought it would be too easy to bump so I turned it off. Then as I started testing my game saves I decided to try it out, and it actually is much nicer than having to cycle the power between games. It might get pressed accidentally if you leave a game running in your pocket or bag, but otherwise I think it takes a firm enough press that I'm not worried.
Haven't had it long enough to judge the power usage, other than to say I don't see the power light turn red as often while loading/saving games.
I also specifically only bought the X5 and not the X7 - while save states might make some games easier, I decided I didn't really need them. As for the RTC, there really are only a couple GB games that use it, and none I want to play hard enough with the RTC features to warrant the extra cost. I've already played Pokemon Crystal a bunhc in the past without an RTC and I didn't feel like I was missing anything critical.
Also I do like to play on a GameBoy Pocket at times, and I was too excited to wait for Krikzz to release a new hardware revision of the X7 that addresses the power issue. The X5 boots fine on my GBP, though sometimes on the first cold boot I have to turn it back off and on again for it to load (giving the power time to warm up). After that first boot, using the button to get back to the menu works fine for me.
Overall I'm very happy with the upgrade, I'll probably put my regular EverdriveGB into a spare GameBoy and take it to work.