One of the critical attributes of a good sidemount course is the personalized set-up and configuration of the user's rig. It's critical because it has such a direct impact on the rig's, and hence the diver's, in-water performance. Set-up/configuration is considerably more 'involved' than with BP&W... and light-years more complex that strapping yourself into a jacket BCD.
With this in mind, a decent sidemount instructor will always recommend that the student buys/brings their own rig to the training. The course will start with a comprehensive 'workshop' to get that rig set-up correctly for the individual diver. That way, they leave the course not only with the skills and techniques necessary, but also a refined and perfected system in which to dive afterwards.
Different sidemount systems have individual nuances. It's quite ethical for a sidemount instructor to declare which rigs they have experience with - as those are the systems they can most efficiently configure for the diver. There are plenty of less-ethical, or less qualified, instructors out there, who won't inform potential students of their rig-specific expertise; some don't even provide in-depth configuration workshops - so they don't care what rig a student turns up with for training..
Poby is qualified to teach the Razor2 directly through the system's inventor, Steve Bogearts. It's hard to get much more rig knowledgeable than that.
The Razor 2 harness (
the most critical component for set-up) is quite similar to the Stealth 2.0 and UTD systems. They are all of a 'minimalist' approach (
sometimes referred to as the 'English' style) and many will agree they are optimal for warm-water (
aluminum cylinders) diving. They are based around a bare webbing harness, with shoulder and lumbar plates. Lower cylinder attachment is typically to the belt (
no butt plate). An instructor who can dive/configure one system with expertise should be able to translate most of that understanding across different rigs that operate to the same/similar principles.
In contrast, harnesses like the Nomad, Armadillo, Hog, Halcyon etc have different nuances in set-up, configuration and customization. These also operate to generally similar principles and are primarily useful for cold-water (
steel cylinders) diving (
they are sometimes referred to as the 'American' style). They generally have a soft-backplate, donut-style wing and make use of a butt-plate. Again, an instructor who has amassed experience on one of these rigs can generally transpose a level of that expertise to similar designed rigs.
Articles on the British/English/UK and American/Florida 'styles' of sidemount:
Side-mount Rigs ? A UK Perspective | TecRec Blog
sump4.com/sidemount
History of Sidemount Diving - SidemountDivingRivieraMaya
Lastly, there are more 'generic' rigs, released primarily with the recreational sidemount market in mind and not quite sure what type of diving they are designed for. The Hollis SMS50 is a popular example. It isn't particularly specialized in either way - and is easier to set-up without extensive experience. It appeals to newly minted sidemount instructors for that reason. That said, an experienced instructor can still help you optimize/customize the rig well beyond the basic parameters.
In short, there is some real benefit in getting your own sidemount kit before taking a course. Make sure that the instructor has expertise and experience with your selected rig - and can offer a comprehensive workshop to help get you optimally configured.
The Razor2 is a very good rig - especially for lightweight travelling in tropical waters. Poby can certainly ensure that you will get the very best out of it.