i have a VP too, i love it but it could use some more power. i built it stock a few years ago, and now i'd love to get an 18mm RMS cassing and some re-loads for it... i have a few other rkts that cassing would be good for to!
I've only ever really had one prob whith my VP, when i was launching it on a slightly windy day i had the rod angeled a little into the wind (not much, tho) but it was damp and i think that caused the lugs to stick a little on the rod... it didn't make it but 100' off the pad and then came in balistic. there was this kid running after it and i yelled 'dont', just as he was about to get within a few feet of it... he stoped and jumped back (i'm glad some1 listens to me!) and the ejection charge went off right as it smashed into the ground... it was very spectacular, but it crimped the BT. that was all tho, and i just cut out that section and re-glued it... should be good to go again!