I'm maybe one of the bigger Rusev marks. Probably the biggest non Bulgarian one if the guy whose signature intrigued you.
He's an absolute monster, former power lifter, apparently considered for the 2012 Bulgarian powerlifting Olympics team!
He isn't the best in the ring but he has great potential. I'm not sure about your knowledge of wrestling in the last 20 years, Batko/Mike, but he was trained by a famous member of the Anoa'i family known as Rikishi, and in-ring is very similar to another member of the family, the late Umaga. That means he can run absolutely rampart in the ring if called up to the main roster.
It depends on where you live on how you can watch NXT. To watch it legally you can watch it on Hulu or WWE.com and maybe even television - there are multiple illegal places though
NXT isn't quite like Raw where the same guys show up every week though. The guys that show on the weekly televising change. Sometimes a person isn't on for a week, maybe two weeks, or maybe is on two weeks in a row!
777 mentioned how he is limited like most big men, however Rusev is one of those super agile big guys, so I don't think grouping him with the 'normal' big men is fair.