Thanks for sharing your experiences....
Yes there is some doco'd WiFi issues... Some can/will be rectified.
There's at least 1 issue with using BT at same time as WiFi too.
It's a WontFix & is to do with poor quality of BT audio or it dropping-out.
I suggested an alt workaround, but they haven't responded as yet.
Re 3G, most anecdotal reports suggest it's def. better than N900 but YMMV.