I have one. Bought one Sunday as an upgrade to the gTab for me and handed off the gTab to my wife.
And overall, it is an upgrade. Honeycomb stock out of the box. Screen is much better, no problems with viewing angles. It weighs more and is slightly larger, but I don't notice. And with the weight and the textured back, it is actually easier to hold onto than the gTab.
Also, GPS, full size SD, user replaceable battery, and rear camera...all big upgrades over the gTab. Not as much modding yet, and the bootloader is locked, but it's coming.
The few negatives over the gTab: price (obviously), the charging cable is a laptop-like brick, and the SD card fits in the top and sticks out slightly (vs being tucked away in the gTab). Volume and portrait are the reverse...not so much a negative, but having to get used to.