Yes, a lot of the decision comes down to why you're testing.
If you just need that 130 (or lower) for admission, I'd go with the WPPSI. Ceiling issues probably don't matter so much for that.
If you're looking for DYS admission or wanting to get a truer, fuller idea of just where your child is really operating, I might suggest waiting and taking the WISC. The SB-V just seems...finicky. JBDad's son had the same sort of issues my son had. Both tested GT on it, certainly, but even the experts felt that our kids' true potential just wasn't being shown. And both our kids seem mathy (or at least pattern-y) AND verbal--like yours in that regard, G3.
OTOH (A third hand?), if you need a fuller score right now for the purposes of major educational choices, I'd probably go with the SB-V, but with the expectation that you may be testing again on the WISC in a year or two if the results are as unclear for you as they were for JBDad and I.
It may just be that a certain kind of visual-spatial kid is not cut out for the SB-V. JBDad's son and mine really do seem to be cut from the same pattern-crazy, science-heavy cloth, so I was not at all surprised that his son scored much as mine did on the SB-V. I also expect him to kick behind on the WISC's PRI when he takes that, just as my DS7 did.
What does that mean for you, BBDad? I have no idea, given that I just told you that under certain circumstances, you might want him to take any one of the three tests! (And you only asked about two!) :p
