The first regulator I bought was a Scubapro. Why - my course director and his staff recommended it, though of course they were working out of a dive shop and were more than likely getting commission! At first I thought it was great, though when it needed a service, it really had to be serviced. It would start to breath really poorly, so much so I didn't like using it and used the rental gear from the dive shop I was working in at the time. As I was living away from a decent service centre so it was difficult to get the reg' serviced properly. When I did get it serviced it always came back from servicing cleaner, but not much better and I'd have to make adjustments to it myself to make it breath better. Then it would last maybe 3-4 months before if NEEDED to be serviced again. I like to do my own servicing, but the G500 and that standard of reg is not all easy to set up right without all the scubapro tooling and equipment to get the breathing rate exact.
In the dive shop where I first started to work there were lots of really old and well beaten up Aleks reg's. Even though I am from England where they are made I'd never heard of this brand. I used one of these when my Scubapro was out of action and quickly noticed that it breathed better than my scubapro, even though it was totally battered, beaten up and looked like it needed to be binned. I took one apart and noticed how simple it was. Later I ordered a few spare parts and the service kits for 7 reg's (cheap as well), fully cleaned and serviced them all. All these reg's went back into the rental kit and all breathed much better than my Scubapro. Needless to say as soon as I could I bought my own Apeks. I don't treat my dive kit too well as I am often none stop diving for periods of time, however my reg' treats me like a King and has never let me down, ask anyone who has ever owned an Apeks, they will tell you they wouldn't buy any other afterwards.
I would highly recommend Apeks as they are very robust, last a very long time between services and in all my time with my Apeks I have never HAD to have it serviced. I just clean once in a while and when I have time I simply give it to the guy in my local dive kit shop, they have the ultrasonic bath to clean it properly and the right kit to do a better job than I ever could do.
However, if you have no access to Apeks regs at all or have no way of getting them serviced then I'd simply say don't buy one, also don't buy an Atomic or any other reg’ you can't get serviced either. If you do you will have to send it away for servicing each time which will only be a hassle. I would simply go with scubapro, make sure you get to know the guy who is going to service your kit... The reason behind this, I'd say that over 90% of regulator problems happen after servicing. You want to look the guy in the eye when you pick yours up and say is it all OK! This is serious, I ahve taken many divers out on dive boats and at resorts and a huge majority of problems relating the reg's comes after they have been serviced.