I just decided to try this last night (today is our firs day using). My 6yr old and I have been doing Oak Meadow thus far, the first grade seemed a bit slow, so we decided to try a supplement.
We're doing the first grade on T4L and a few hours in, love it! It's fun for her and very engaging. Honestly, she thought I bought her a new computer game, which I'd consider a benefit.
I say to go ahead and try it. I read this thread yesterday and signed up last night after doing a bit of reading. So far, I'm really happy.