Go for retake. If your practce scores are between 46 and 50, it would be shame to end up with 44. If you keep your Verbal on current level, you'll have somwhere around 720-730 with better Quant, which is much more competitive score. Difference between 690 and 700 is purely psychological - nothing could be concluded of difference between future academic performance of two candidates with such scores - but 700+ score could be self-confidence booster for you.
If you don't retake, you will ask yourself untill the end of your life had you been denied on some schools just because of that "6" in your score. On the other hand, if you retake and score 720-730, you will know that you have done everything you could and that, if denied, you have to blame some other weaknesses in your profile.