The 2900G promises a lot and delivers much of it. Where else can you get everything that the 2900G provides, and for around $200, and without per-user license requirements or paying for the ability to get firmware updates?
The part that's not delivered, however, is a stable, finished product. The good news is that features and improvements are still being added. The bad is that some of the current features don't work and you'll get to pay for the privilege of waiting for those to be fixed and helping to debug the new ones.
This method of product development is encountered too frequently, methinks, by today's networking product consumer, and DrayTek appears to be part of the pack. DrayTek's U.S. presence, however, is small compared to the major manufacturers, being supported by a single rep. (Guideband.com). Products are only available direct and through "affiliate" resellers and all product support is handled via an on-line trouble ticket system and user Forum - phone calls are not an option.
The bottom line is that if you're expecting a polished product similar to those from the "big guys", you'd better pass the 2900G by, no matter how tempting the feature set. And even if you're comfortable helping (and paying!) to polish a diamond in the rough that has a combination of features you won't find anyplace else, I'd wait a few update cycles to let someone else shake out the bugs and see whether the VLAN and Bandwidth Controls really do get added to the wireless side.