I've been using the W77C32 in production for a little over a year now. It works quite nicely, good performance and has dual uart, dual data pointers, extra external interrupts, and capable of waking up from power down mode with external interrupt (standard 8051 requires a reset).

Yes the documentation is less than stellar. I have been known to look at the corresponding datasheet from Dallas (DS83C320 I believe).

I have run into a problem that I would consider a bug, but did get support from the local US FAE, and from engineers in Taiwan.

Dennis