Couple things I've noticed since I started using it:
- The Java launcher sucks ass. For the unfamiliar, or those without Java installed, the "jnlp" format is just an "unknown file", and without a hint on the page saying "this is a Java web application link file", or providing an alternate launcher, it prevents it from presenting a truly "polished" appearance.
- Setting the GPU "relax period" too high, say 500ms, on my miner box, works OK but silently shoots CPU usage through the roof. CPU usage translates directly to excess wasted power/heat, so perhaps a slider could be put here instead. The client, being as robust as it is, could probably auto-detect the interval where CPU usage begins to rise - likely caused by trying to update the display quicker than the GPU comes back from its loop(s). Personally, I'd rather have an unresponsive desktop and a fast miner using 0% CPU, than a zippy desktop without a monitor attached!
- The graphics are awesome.
- The UI design is awesome.
- Unlike other miners, it properly detected the 128-bit memory bus in my 6770, and accordingly set the work size to 128. Other miners have defaulted to 256. This will certainly result in amazing performance boosts if this auto-detection continues to work properly for other new users, many of whom - not active users here - don't know the difference.
- Speaking of which, if there is a known issue with the driver/OpenCL setup on the miner PC (like running Catalyst 11.8 or something), and it's getting poor performance/high CPU, bring it to the user's attention and I can guarantee you'll have the most efficient pool and most popular client around in no time
Just my "kinda putting on a black turtleneck and jeans while I say this" sort of friendly tips
The thing looks incredible, and as long as nothing terrible goes wrong (like "hey, why the hell is my balance still 0?" or the like - haven't run it long enough to see, of course), I hope to run this for a while 
