Obviously, the more bandwidth that's available, the better the performance of any terminal server. In relatively small environments with a limited amount of network traffic, 802.11g and 100Mbit/sec. Ethernet appear adequate. In fact, in environments like a small office or a classroom with fewer than 10 connected workstations, performance is actually better than one might expect with live screen updates of text and graphics. This is true even when working with moderate-size Photoshop documents with multiple layers and filters.
That said, most environments -- particularly those with more than a handful of computers or devices -- will probably require Gigabit Ethernet to ensure reasonable performance.
Obviously, enterprise deployments will opt for much more powerful hardware, and Apple's Xserve provides an excellent platform for AquaConnect. Although using Office -- for example, on a low-end Power PC Mac Mini running AquaConnect -- led to fair performance, CPU usage for simple Word tasks being run through a single AquaConnect session resulted in about 35% CPU usage. Running on an Intel Xserve, CPU usage for most Intel-native applications with a single user was well below 10%.
Scaling usage patterns for AquaConnect in an enterprise environment is likely to require a fair amount of testing to determine the exact number of user sessions each server can realistically accommodate, depending on the precise mix of applications involved. The suggested RAM allotments per user session, which appear to be extremely realistic for most environments, are probably the best guide.
One thing worth noting with regard to performance and memory requirements is that AquaConnect has made strides in enabling the reuse of code and resources being accessed by multiple users. This means that if two users have open sessions and are running a similar set of applications, the actual system resources required by the server are not going to be doubled. This is an excellent feature, though again, it can make finding the precise mix of applications and number of realistically supportable users a little challenging without a fair amount of testing.
Overall, I have to admit that I am rather impressed with AquaConnect. It provides a stable and well-performing solution for providing terminal services from Mac OS X Server. It offers a surprising level of simplicity of setup and ease of use and manages to support a very broad base of clients. For an initial release of such a broad product, AquaConnect's engineers deserve a pat on the back.