In terms of talent comparing ND OL to the Bama OL is a rather obvious mismatch. However they are talented with what I'd grade as a very good LT, LG, & C combo with a servicable-to-solid RG & RT combo. The strength is on the left side of the line.
However evaluating them as a unit and their fundamentals I've been impressed, surprisingly impressed. I generally don't watch much ND fb, but caught pieces of several games this year and have gone back to espn3 and watched them vs USC, BC, & Oklahoma. They hold their own, aren't great, but do the job with fundamentls in the passing game. However in the run game they impress. They zone and man block. The impressive thing is how low-hard and quick they FIRE off the snap. They are tenacious, lacking the talent of maulers like Fluker, Warmack, & Steen, but are every bit their equals when it comes to firing off the ball and staying low. Translation, they're fundamentally sound and know how to play the game. They're not small either, all are listed at 300+, but just over and most are 6'4" or better.
To boot the ND run game seems to be a 'seam' run game where the RBs run less to a hole, but look for a seam/crease. On that note Riddick is legit and aside from Gurly and possibly the LSU freshman will probably be the best RB Bama sees this year.