Judges of the "complicated" wing of the Republican party end up being surprises. When Judges are unprinipled, things get complicated and harder to read or predict. Read this speech by Janice Brown to the Federalist Society. http://www.rushlimbaugh.com/pdf/JBrownSpeech.pdf Janice Brown is very uncomplicated, very straigth-forward, and very conservative. There is no need to worry with some one like her because she is fully grounded in principle. Can you imagine Souter writing that speech?
Bush is looking for a strict constructionist, which will only be ascertained by examination of the candidate's decisions and writings. We are unlikely to get any surprisesmin the candidate's future decisions...at least until he/she has been on the court a while.
You cannot guarantee how people will vote while on the Court. You can only do your best in picking one whose judicial philosophy seems to be closest to your own. After that, it depends on the judge's character.