My 2 cents. Back in August I started on #19 and took them in order, and I just took #42 today.
In general, I'd say that the tests are pretty consistent, but I do see a trend towards greater difficulty combined with greater consistency. In other words, the newer tests are more difficult on a per question basis, but they are also more consistent and thus more predictable. This seems to be particularly true on LR, a bit less so for AR. Apparently #43 has a killer RC passage-- I'll find out on Monday. Perhaps harder RC and slightly easier games will be a continuing a trend. Only LSAC knows.