REDANZL  Very responsive connecting to a 400 MHz Linux box on a local network. It's a very simple app, and as far as features go, there's not much to it, but it serves my purposes completely. I had tried Chicken of the VNC, which was unusably slow (5+ second lag!), and hogged > 90% of my 1.67 GHz PPC Powerbook. I was going to give up on using VNC at all. I gave VNCDimensions a shot, and it's almost instantly responsive, and only uses 40-50% of the CPU. It hasn't crashed yet. I'm very pleased.  
(Version 0.7.10)

WACKYMACS  This application is very unstable under Mac OS X 10.4 Tiger. It often quits itself when I try to connect to a server. "Chicken of the VNC" is better than this by far, as well as being popular and having a nicer interface.  
(Version 0.7.10)

ANONYMOUS  I can't really review it because I couldn't get it working. Every time I try to create a new connection it says "Unable to create a new document". I didn't see anything about running it on OSX 10.3 on the website, so that might be the problem.  
(Version 0.7.10)

ANONYMOUS  Works great. Would be nicer if command-tab still toggled OS X apps from Full Screen mode.   
(Version 0.7.10)

ANONYMOUS  Over a local LAN this is the most responsice VNC client I've used. Over a low bandwidth link, though, it's horrible. Definitely going to be part of my toolkit: between this an CotVNC (which is great over a low bandwidth link but doesn't seem to benefit much from a high bandwidth one) I've got pretty much every base covered.  
(Version 0.7.10)