You will potentially get very biased opinions on this one, one way or the other. For a lot people on here, the VF-4 has been a holy grail. YF-30 has got that "new hotness" going for it, but both valkyries are so disparately different they are hard to compare 1:1. I have a YF-30, but not a VF-4g. Quality-wise, my YF-30 is awesome. Built extremely well. I have not heard of any rampant QC issues on the VF-4's (Yamato or Arcadia). Maybe do a trial run with your friend for a week or whatever? If he is a good friend, and lives close I don't see the harm in it, unless they are ham-fisted.