Google says that Honeycomb won’t “require” a dual core CPU, but that’s clearly the hardware platform that it’s being primarily targeted at. I wouldn’t bet against it, but I’d definitely be leery of its performance on existing devices.
GPS doesn’t need 3G to function though the Android software built around GPS typically pulls map data from the network as needed, so unless the device can talk to Google’s servers while you’re using it (which typically means 3G unless you’re sitting at home, in which case why do you need GPS?) there isn’t that much point to having live GPS data. You’ll know your lat/lon, but what good is that if you don’t have map data to go along with it?
To really use the GPS in a practical manner you’ll either need to acquire software which downloads map data to the local device so you have it regardless of network connection, or else tether your Galaxy Tab through something else (I do this with my ASUS Transformer. It has no 3G but does have GPS. I can data tether it through my Android phone so that it can get map data on the go even though it only does wifi).
Update: I have 2 friends who have bought and returned the Motorola Xoom. Both have access to iPad 1 or 2, and found issues with Xoom and/or Android that cannot be overcome in their minds. They managed to talk me into waiting even longer for the flood of other brands of Android tablets.
IIRC the reasons: Xoom’s display is not as saturated as the iPad; Android’s store doesn’t have the massive amounts of apps; … I can’t remember the rest.
One guy loved the flexibility and live-ness of the Android home pages.
With the new update to the Xoom, it seems very solid now. The browser is totally badass now. The quirky issues that it had when I first got it seem to have been resolved, and with the new little swype app thing (Flex 9t or something?) that I got for free from the Amazon app store on the day it was offered, the Xoom does exactly what I want it to now.
I’m still extremely happy with my ASUS Transformer (though it is priced outside of the core of this discussion, especially if you include the keyboard dock).
I tend to use it in netbook mode about 80% of the time because I just really like using a near-full-size physical keyboard when typing, then just pull out the tablet part when doing lazy couch surfing stuff.
The Transformer has 100% convinced me that I don’t ever want another dedicated tablet, though I do very much always want a netbook that can become a tablet as needed, so I’m pretty much never buying any tablet on any OS in the future that doesn’t reuse this convertible form factor (being able to plug in a bluetooth or usb keyboard to a basic tablet doesn’t count, it loses a lot of convenience by requiring a secondary case with extra accessory storage to tote the thing in).
I also like the transformer with the keyboard dock but the one I bought had major light leak issues so I sent it back and after reading about a lot more issues like mine, got the Acer Iconia. Very happy with it so far even without a nice dock like the Transformers.