I would have to agree with the above poster. I don't feel that medtronic's heart is in CRM anymore and they are just riding past success and name brand.
Sorin would be the "worst" but only because of small market share. If you actually look at their technology, they have some pretty damn good stuff; they just have a marketing problem and lack of personell to push it.
Biotronik has great stuff too, they have the lowest incidence of inappropriate shocks, but again, customer service is lacking due to personell issues.
Boston is a cluster fuck. Goddamn headers falling off the Teligen, getting ripped off the market and a recall on the horizon. Ray isn't getting shit done to change the brand.
St. Jude - nuff said they got their act together, their corporate managing is just a pile of shit and they treat their subordinates like ass clowns.
so to rank
Sorin (they are climbing, believe it or not, i know 2009 went down but mark my words)
Boston Scientific (declining)
Biotronik (climbing)
Medtronic (they are sliding)
St. Jude (it's good to be king)