Rentals are well...
.rentals. They get dragged, abused, used more often than most, see probably the least amount of a service technicians time than any other customers regs since the shop gets
paid to work on customers...
Edit
They take a lot of abuse, are often lower end, older models and in some shops likely don't get serviced as often as they should. I know of one shop on Maui where rentals were serviced when someone complained rather than on any mfr's approved schedule.With a lot of rentals and a rotation schedule they probably got 4-5 years between service on many of them.
A Scubapro Mk2 was first introduced in 1962 - I still see them in use in rental fleets today. One reason is that in the case of a complete reg failure it will still flow some air rather than shutting off your air supply. It's an extraordinarily rare occirrence - in 35 years I know pf one failure that might've been the product - all the others were improper servicing.
After you buy your own regs and have them serviced - check them before you take them on a trip somewhere. I know of 3-4 failures this decade where the tech simply made a mistake - and it's not rocket science.
You're just not using the best equipment, pool gear tends to be the most overlooked because if you're drowning - in many you can just stand up.
I dive Atomic regs - with 2nd stage swivels.. Twice I've almost dropped it out of my mouth at depth while focused on something else - it's so "not there'.
After class, decide on a good reg. set you can afford. In the case of the Atomic line their $410 model
breathes the same as their $1700 model - the difference is features and materials used. Other reputable brands are similar. I'd be divng Scubapro today if a local dealer hadn't shown me Atomic's line/features. At the time the 2 year service interval was attractive - now many offer it.
I don't suggest putting a lot of money in new regs before you certify - once you use it, it's used and lost 50% of it's value when you walked out the door with it. Craigslist and eBay are littered with good deals from people who thought they were divers for life.
I wouldn't be in a rush to gear up - likely a lot of what your know now is from your shop and they may have ulterior motives, dealer agreements, sales quotas that affect what you're shown. Don't think it's coincidence that your instructor dives gear they sell every time you see him. I have an instructor friend who is a long-hose, hogarthian backplate diver but since his shop is a Scubapro dealer every time b4 class he snags one of their rental setups and uses it in class.
Some legitimately also want to help - one of our shops talked my buddy down from a $500 wetsuit to a $160 one that works as good. Don't believe the mfr's hype always either. And don't believe anything I write w/o validating it first either although I'm about as agnostic as they come, I have no shop/mfr relationships and until recently I volunteered here.
Some mfr's lines set what they call MAP - their dealers have to advertise that price online. At least two of the larger online retailers - one in Dallas and one in NYC have offered me a better price over the phone without asking for it.
Every other mfr. has similar models in their line at all price points. Any new balanced regulator you buy will perform equally well everywhere - balanced means that the reg will breathe the same as the tank pressure deccreases during a dive. I think's hard to actually buy an un-balanced reg now over $200.