Yes, the 9mm P99 Compact is available in AS and QA triggers. The .40 Compact is only available in the QA trigger.
No issues I've heard of with the compact model other than the limited availability of spare magazines.
There was a problem with Walther America putting the wrong backstrap in with the last 4 Compacts we bought from RSR. They had put in the full size backstraps from the P99 instead.
Walther America still has not rectified that problem for us yet. They claim they are still waiting on them to arrive from Germany (we're talking about a 50 cent part that they don't have in stock)
James