I own a Flyer, picked it up in June. As a business tool, it's great. I use it for mobile access to my corporate calendar and email. I tether it to my Nexus One when out of WiFi range.
1. Speed is not an issue. The only lag that I dislike is the Sense unlock screen. There are settings and tweaks that can change the animation, but I haven't bothered to do anything about it.
2. Honeycomb is sort of a question mark. I was supposed to be out by now, but like you said there aren't a ton of apps yet. HC 3.2 (I think) is supposed to support 7" screens. I suspect that HTC may still be waiting, and updating Sense. I'm interested in seeing HC on the Flyer, the updated GMail app is really what I would like. The build in non-Gmail email tool is great.
3. The stylus is disappointing. I got it for free so I'm not that worried about it. There aren't a lot of apps that use it. Perhaps everyone is waiting on HC? HTC just released a larger tablet with the same pen and released the APK for it, so maybe that will kick start it.
4. 7" is not ideal for lots of web surfing, but it does a fine job for most things. 7" is ideal for taking with you. The Xoom and other 10" class tablets are nice and easy to use, but in my opinion are too big to drag with you all the time.
Depending on the video games you want to play you might find the Flyer doesn't pack enough power, you'll just have to go somewhere and try it out for that. For everything else you should have plenty of power with everything else.