I got one too and I love it! and I'd say 300 watts is way conservative.
I believe mine is listed as 500 watts. I use one side of a Stewart World 2.1 to power it and that puts out 650 watts at 4 ohms. I never turn the Stewart up all the way but I let a guy use my rig one day and after he was done playing discovered he had cranked the Stewart full volume while he was playing - the cab didn't mind at all, sounded great and didn't bat an eye.