I wouldn't recommend anything but H.264. There is no better codec.
First of all, I post text based tutorials in H.264 without a problem. I don't use Camtasia anymore, I use CamStudio (it is free).
Maybe if I type into this window and record it at the same time I can show you the quality of the H.264 codec.
I record 24 frames per second into an AVI that uses the Lagarith lossless codec. It makes a very large file, but I have the room on my RAID0 and Premiere Pro likes it just fine. I added a title just because you said that is what you do.
I exported the following to H.264 using the YouTube preset without changes. Sorry, but I realized after the fact that the title is a little soft. That is one of my normal font styles and I forgot to make it sharper. I watched this at full screen on a 1920X1080 monitor and it looked pretty good to me. Pretty darn close to what I saw on my screen when I recorded it. I put the video on one screen and this page on the other and I have to say "Is it live or is it Memorex?" (Sorry, old commercial for audio tape.)
So I have to ask, what is it that is causing you trouble? The way you capture or the way you export, or both? Also, have you played it back a couple of times. Sometimes I don't get the HD to show up clearly on YouTube until the second time through. That is not the fault of the codec though.