I did a swimsmooth weekend 3/4 years ago. Was very good.
I also did a weekend coaching session which was with Archie Brew a few years before that. Archie was really very good, spotted some big flaws immediately and fixed them.
The Swimsmooth course I was on was led by Paul Newsome and he does know his stuff. Swimsmooth has grown so other coaches may be leading the course. The coach is the important thing - Swimsmooth or any other brands dont really differ much in what they are selling you - swimming is swimming (although TI might try to say they are different...).The swim stroke that most courses will coach you in is probably pretty much the same. An experienced coach will spot more things, so have a good look at the course leader and assess what they have done rather than just go on the brand.
Nice thing about Swimsmooth is all the stuff they put online, and they have been good about getting on forums and answering questions. There was also a good vibe on the day - which helps.
I did Swimsmooth as an improver rather than a beginner, but it seemed to me that all levels were well catered for and came away with improvements.
I would recommend Swimsmooth. They are very good.