I have the V300H and a V6. I bought the V300H for a backup but I have found it to be a great amp for my "first." It's amazingly warm and punchy for s.s. I attribute that to the V-type preamp and Trace's excellent and conservative power supply for the ss section.
I am a BIG fan of the V6 -- I've owned it for almost 6 years now, and I can't imagine ever replacing it, but the V300 is pretty damn close! And weighs less than half as much!
The V300 will overdrive pretty well. It's a preamp overdrive as opposed to a poweramp tube saturation overdrive. You can really never replace or adequately imitate the sound of power tubes being pushed hard. It's why we "valve-oids" tolerate the inconveniences in the first place. Some folks say that some of these simulators can come close, but I don't agree.
I suppose that I'm waffling here. It's because I know that the V300 won't perfectly imitate a "real" tube amp, but it does give you an amazingly warm, clear, articulate sound that makes this amp unique (imo). It will get "grunty" but probably not exactly like your current amp. They sound different! It will cut through your mix and never sound harsh. It also does low volume gigs amazingly well.
The V300 preamp is a rather quirky fellow. The bass mid and treble interact quite a bit with each other. The bass and treble boost switches are also different than your average. The Mid boost pull-out is amazing. Use with care. This style of preamp can be off-putting to someone used to the regular tone controls and graphic eq. The V-type is a totally different animal -- and I suspect it is one reason why it can be a love-hate relationship. I love it -- but it takes a little time to get used to.
One caveat: The amp is 280 watts into 4 ohms. Is your Ashdown 8?