Generally, you want to use VB (provided you're fighting an opponent it works on) in conjunction with the b312 and 334 strings. The reason for this, aside from just keeping you safe and giving you frame advantage, is that those strings are slow and don't give Raiden any particular advantage on block. Moreover, it creates a guessing game, since the only way your opponent can counter them aside from just taking the chip and waiting for an opening, is to guess and duck the VB and then punish (usually with uppercut). However, all hits of the strings can be special canceled, so you can insert the VB anywhere (or a teleport, or whatever, for mixup). So if you do b3~VB, b31~VB, 33~VB, etc., but then you actually finish the full string (which ends in overhead), your opponent has to guess when there'll be an opening to duck and when ducking will cost them 30%+ of their life bar.
Right now, you can do a lot after VB. f24 is the fastest, and usually safest option. In fact, I'm not sure if anything can interrupt it if you have good timing, but if so, it's only the very fastest stuff. 121 is also a good option, since it's very fast, but the first two hits are duckable, so you're taking a risk. You can also use b312 after VB, not because it's fast (it's not), but because it reaches a deceptively long distance, and if your spacing is good, you can catch your opponent that way. One of the series I use most often is to do some block string into VB and follow it with f24. If that hits (it often does), you can link in a superman (or a 40% combo in the corner). If it's blocked, I'll throw out a b31 (with or without 2 at the end), because the combination of blocked VB and blocked f24 pushes them quite a ways away, but not out of b3 range, which is very deceptive. Also, in general, b312 is a good follow up to f24, though it's not 100% safe.
Keep in mind that the main thing that makes the VB dangerous is the same thing that will still make it dangerous after much of the frame advantage on it is lost: the mixups. Don't just use the same sequences, like the one I listed above. Throw in teleports, throws, low pokes, and even armored ex moves if your opponent is poke-happy. If I have the meter and life to spare, sometimes I'll even end a string in an ex lightning bolt to bait out counters, since even if I take a hit, the second lightning bolt will come around and tag them in the back, allowing me to combo.
I should note that a good chunk of the above comes from stuff I learned from TomBrady's guide and then expanded through my own play experience, so major cred goes to him for being an innovator.
