I just installed a Raritan Dominion KX432 to take over for a few smaller Raritan units, including a 10-year-old Master Console IIx. The Dominion series' density is high, the physical units are small, and they have all the features I need in an IP KVM, all contained in a single unit that doesn't require an additional physical server like the Avocent units. Their Java-based console app seals this deal, since I work on Linux and Mac OS X workstations. I've found that the console app can be somewhat flaky over higher-latency connections, but still usable, although working with the networking prefs can improve performance. As a front-of-rack KVM, the Dominion is as solid as any that Raritian has produced... and my recently-retired Master Console IIx can attest to that reputation.
The next part of this series will be workstation hardware and OSes, monitors, phones, and the rest of the little bits. Stay tuned.