It depends on where you are at.
In Colorado Springs it is not oversold yet. Downloads are as responsive as the
T1 I have at work. Uploads are slower, but still much faster than 56k.
Outages here are rare, but the latency is pretty bad, so online gaming is
right out.
It is bidirectional, and asynchronous due to hardware limits. FCC regs let them
do 400W on the downstream, but the user site can only transmit 40W back up.
It is very much like a cell phone, with the broadcast partitioned into
specific sectors, so different sectors might also experience differences in
performance.
If you are being offered it in an area that is not saturated it can be as
good as DSL or cable (since I'm in an area that can't get DSL or cable yet).
Around here there are stores that are set up as demo sites so people can see
the performance for themselves. You might want to check for sites like that
in your area to shop it around.