Straight out of the box it definitely is not the amp you would look to for modern high gain tones. While it does a very good Marshall type gain, you will definitely need some boosting to get it into modern high gain territory. I've had mine for a couple months now and it's a really great and versatile amp for everything up to Marshall type tones - it's does beautiful Fender cleans, nice chimy VOX sounds, and some really great British rock and metal type tones, but you would probably be better off looking elsewhere if your looking for Mesa or 5150 type high gain.
It's the perfect amp for me, but then again I generally play more heavy rock than modern metal. The ability to experiment not only with the numerous switches for the voicings and tone characteristics is just the beginning with this amp - add in the fact that you can almost through any tube at it from EL34s, KT77s, 6V6s, 6L6s, ... It's cathode biased and no adjustment is required to experiment with different pre and power amp tube choices.
It has an effects loop so you could probably get you gain from elsewhere, and it also takes pedals really well from the front end. As I said - for me, it's the perfect amp, it's gets me such a variety of tones that are all very very usable - it's really difficult to get this amp bad sounding, but it does not do modern metal gain I'm afraid without some help.