Articles are popping up all over now with more information on the gen 2 so I'm going to summarize as best I can.
The screen resolution is roughly 25% higher than the gen 1 providing an overall 50% more pixels at 1832 x 1920 rather than 1440 x 1600. This runs at 72hz at launch with "experimental" 90hz support coming soon. The panel is changing from OLED to fast switch LCD. Memory is 6 GB instead of 4 across the board and is available in 64 GB and 256 GB capacities, both using the Snapdragon XR2. The new chipset is twice as powerful as the 835 however the 835 was overclocked in the quest 1 so real world performance remains to be seen. Battery life on the headset is about the same, between 2 and 3 hours. Eye focus is one of three positions, 58mm, 63mm and 68mm adjusted with a switch in between the lenses. The head strap is a slight improvement out of the box but you can also buy one of two extra attachments that make it fit better; one includes a built in battery pack to double battery life. Changing the strap is extremely simple, just snapping the old one off and snapping on the new one. 3rd party strap solutions may be a very real possibility. One headphone jack has been removed so current specialized headphones won't work on the new device. The built in speakers are the same as the 1 but are further back on the headstrap and reportedly provide a deeper sound. They aren't allowing quest 2 exclusive titles at this time so all new games will still work with the 1.
The controllers are more efficient; 90% battery after a week of heavy use according to one article. The general consensus is that they last between 2 to 4 times as long with oculus officially saying 4 times longer. They also changed the battery covers from magnetic to plastic friction fit and added a thumb rest to the design. This makes the controller larger and, according to some, more uncomfortable. Controller tracking is better according to oculus but most reviewers are saying they don't notice a difference with one or two mentioning misses in beat saber happening more often. Oculus originally said the new controllers would be backwards compatible but reviewers are saying they aren't. I have yet to find official updated information regarding compatibility.
Logitech is going to sell two different specialized headphones for it. One is a set of earbuds and the other is a full set of over ear headphones and both should work with the quest 1. Facebook is also selling what they call a fit pack that includes light blockers for the corner of the lenses and two different sized face pads. VR cover will also be selling face pads although there are no details on them yet.
It appears it's a great headset for first buyers but not worth the upgrade if you already have the gen 1*. I'm finding more articles as I go and editing in relevant information as I find it. Let me know if you find anything else and I will add it in including answers to questions if I can find them.
Edit: I clarified below on whether or not to upgrade. TLDR; Right now there are pros and cons for each generation of the quest. Your best bet would be to read some of the reviews yourself if you have a gen 1 to find out if any of them are deal breakers or, even better, try to get your hands on a gen 2 either from a friend or an in store demo and try it before pulling the trigger. Personally I don't think I'll upgrade. Yet.