Do the places you train clients require that your certification come from a national organization? (i.e. AHA or RC)
If not, I’d encourage you to focus more on who’s instructing the class rather than just what’s being taught – especially if you’re re-certifying. Similar to what others have said, having an instructor with personal experience is important to me each time I renew my CPR/AED certification. This would include EMS technicians, firefighters, etc.
A firefighter instructed the class the last time I re-certified and he brought up a good point: for most individuals (should an emergency situation arise), our job is to lead or help manage it for the few minutes it takes for the responders to arrive. Would you disagree?
Best of luck to you finding the right organization with the right instructor for what you hope to gain from the class!