My DD5 didn't like xtramath either because of the "time pressure."
We've found that www.fun4thebrain.com is a free site that has a number of fun no-pressure games for practicing basic math facts. She especially likes the games with the MURB monsters: http://www.fun4thebrain.com/murb/murb.html
It doesn't track your progress, but you can choose what you want to practice. It has fun music and graphics, and best of all, there's no pressure.