I bought MyWi (No Rock) v3.4.3 through Cydia/Appsidy. I've tested both Access Point and USB tethering (but not Bluetooth).
Access Point tethering worked fine (WEP key enabled). I didn't leave it running long due to all the posts on battery drain having both WiFi and 3G on at the same time.
USB tethering worked too (on computer with iTunes 9.x installed for USB driver). I was surprised to see a "Internet Tethering" option appear under General->Network in the iPhone's Settings app (but I guess it was put there by MyWi).
I do not use MyWi normally so I don't have any longer-term or heavy usage notes. I just purchased it as an emergency measure, or maybe for possible computer use on vacations. One of the best utilities I've purchased for $10.
Tethering -- another cool thing my iPhone can now do too.
(Also just throwing in my $0.02 since I haven't seen any posts on the No Rock version of MyWi. Obviously, YMMV.)