WORLD28  Excellent program for CVS use. The version 7.01_1 is not very stable (java at launch fails). Config PPC G4 (powerbook) 0S X 10.5.5  
(Version 7.0.1_1)

CONNER_BW  Prior to this SmartCVS I was using Heilancoo's free MacCVSClient. A lack of updates and a general lack of UNIX conventions eventually forced me to look elsewhere. I ended up paying for SmartCVS and I have no regrets. It's fantastic.  
(Version 6.0.8)

SEMIOTICMONKEY  the foundation version i tried out has, in 6.0.7, still the spaces bug (as 6.0.6). every time you switch to smartcvs on command+tab, it don't holds focus. No way to wake up it from his catatonia without switching manually to its assigned workspace.

the same don't happens when in dock minimized state.

in this version finally it sticks with the color theme preference (no more blue scroolbars when you have graphite).

features wise it is a very good client (yep. on Mac it is a godsend. No tortoiseCVS here and you are in the cold if you don't want to install the entire apple developer tools only to have this little damned cvs client, via devtool or fink or macports it doesn't matter). i still use Eclipse (cvs+diff+merge) cause the spaces bug slow down my work habits. Anyway i suggest you to try it out to check if it fills your need.  
(Version 6.0.7)

M!K3  Well, I'm using smartSVN (their Subversion client) for some time and I'm very happy with it. Now we had a project for CVS. It was natural to give smartCVS a try. Incredible, what these guys squeeze out of that old VCS! It's by fat the feature-richest CVS client I've found - what other CVS client can show you change sets or incoming changes (except the one in Eclipse)?

There is only one small issue: compared to smartSVN it is quite slow when it refreshs the remote states (causing new revisions/files to show up) - at least on our large repository.  
(Version 6.0.2)

SCHMELDING  This is definitely the best CVS Mac client I've seen so far, but it has a long way to go. Although it depends on Java like Eclipse, it has a much smaller footprint than Eclipse. But it still has some serious issues:

1. Java. It's still too slow. Develop this in Cocoa and then I'll send you my $70. I'll throw in a hug, too.

2. The interface is better than other Mac CVS clients, but it is still too cumbersome and unintuitive.

3. Price. Others are free. This is $69 for the full "Pro" version when all other clients offer a free full versions. I'm not saying make it free, but the price point ought to be considerably less. I would pay $20, but not %70.  
(Version 5.0.2)