ignite amps SHB-1 vst is just amazing. i've A/B it to IK's ampeg, bias and guitar rig and ignite just floors them, it sounds like a real amp comared to the rest. high end, mids, focused lows. while all of those vsts are great, and second in line is imho ampeg svx, ignite is just miles better. just one thing, ignite is very "hot" amp, so gain should be used more as overdrive than normal gain, in most cases, set much lower than 11 o'clock. i don't know if ignite includes cab in it's SHB-1 bass amp, but imho it sound best as is. ofc you can experiment with some good IR cabs (even ignite has some).
you can download it here
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and it's free. apsolute beast!
next in line are line6/behringer products that while are nice are not the same quality of good vst amp sims. in live band situation, noone would notice sound diferences, but that's another thing. line6 stuff sound better than behringer, but some amps (like mesa boogie and aguilar) sound just to boomy, trick is to tame them with a big amount of compression, and tweek out some annoying midrange "plastic" overtones, they hide somewhere around 300 to 500hz, you have to find them for each amp. since line6 has good eq, that will be easy trick. also it's compressor is foolproof and works like a charm.
just for the info, i have all of the mentioned vsts, line6 x3 live, line6 amplifi fx100 and behringer v-bass amp.
so all in all IMHO;
Ignite amps SHB-1 VST
Ampeg SVX
rest of the IK gang (their SS bass amp is great, especialy when you put solid state preamp and tube power amp, G&K is nice but has some unnatural mids)
Guitar rig5 bass amp (you need to find it's flunky midrange and cut it out, after that it's fine)
BIAS AMP (if you like overdrive and dirty bass, you'll probably like that one the most)
Line6 gear (gazzillion amps, decent sounding when eq'd and compressed)
TSE B.O.D. sansamp DI VST - i'd rate it below the sansamp di sim that's on line6 x3 and amplifi , but hey, it's free so....
TSE Audio - Software
and the last, behringer v-bass amp pro. it's cheap, it's usable, and probably noone in band or audience can tell the difference if you match it's for example ampeg svt sound to line6 x3's ampeg svt.
keep in mid, the difference between them is not that big, meaing that between "best" and the "last" on this list, in live, band situation select few will hear the difference (you included), everyone else will be like

whatever
but hey, i said using VST plugins for live play? WHAT?

yes my firend you can use even that, all you need is a laptop, audio interface and poweramp/box. or even your trusty amp with box, or combo (provided they have fx loop that you can use to bypass it's preamp, KEWL!) or you can plug in direct into PA and be the bassist sound engineers dream about.