The new GMATPrep has the same old questions, so you certainly won't be getting a fresh experience. It is updated to include IR, and you now have the option of purchasing additional quant questions for $25. They've also changed the software so that once you close the program, your problem list is gone. If you want to study your exam, you have to keep that window open until you're done!
As to retaking, I saw that you asked about resetting our (
MGMAT) exams as well. Retaking is generally not going to produce an accurate score. Even if you don't feel you remember the material, it is generally easier to handle material you have done before. If you have improved significantly, you will certainly see some different questions, but there are likely to be some familiar ones, too. If you do choose to retake exams, try to make the experience as realistic as possible. If you see a familiar problem, take the full time before answering, and put the answer you think you *would* have chosen if you hadn't already seen the problem. That way the CAT algorithm won't push you up higher than it should.
So basically, you can retake exams to get some additional practice taking the exam, but you shouldn't expect those CATs to be accurate measures of your progress. If you have a lot of prep to do, I'd recommend that you purchase exams from another company to get a fresh experience, and mix in
MGMAT/GMATPrep here and there.