I started out with the T-20. But I was trying to use it with a camcorder and that wasn't enough light. Then I bought a T-38 and I like the casing, housing, body of the light much better. But that wasn't very bright using my camcorder. I had to get a new camera.
Once I got the new camera, everything improved. I now also have a T-50. I like it a lot, but it's not a cheap light.
Out of all of theses lights, I'd say get the T-38.
There is a new bulb out that you can put in the T-20 called "black Sun" .
The manufacture claims it's much brighter than the regular T-20 bulb / pill. So I bought one, but I wasn't impressed.
Maybe 5% or so brighter.
So My opinion is get the T-38.
CH