Look at regs that can be serviced world-wide. Getting regulators serviced is a big deal. Talk to your dive shop for advice on what regs are serviced most easily.
I had trouble find a place to service my Apex regs. The last time I sent my regs to someone who said they could service them, it took 3 months to get the parts needed.
Thats interesting. I regularly travel around the world for diving (minus the US) and I have found that SP and Apeks are by far the most used regs and easiest regs to get serviced based on my experience. I run Apeks regs and most of my friends do as well or SP and we never have had issues getting parts of service for them. I lived in Indonesia for many years and have dove in probably 15-20+ countries. Plus not to mention I can fully service an Apeks 1st stage in about 5-10min with 3-4 tools on a rocking boat. Very expedition field service friendly.
Why not? We have an Asian office, distribution, and many dealers in Asia.
Another interesting point I have never seen or heard of anyone in Asia knowing about deep 6.
Deep 6 and other knock off Apeks/SP regs (DGX, Dive Rite, TDS, Tecline, HOG, Problue, IST, etc. etc.) you will find are very very very difficult to get parts and service for.
My wife and I am looking to purchase a set of regulators and mainly dive during traveling, our local dive sites are all quarries. I need some suggestions on what regulators to buy. For about the same price ($480) I can get Oceanic Alpha 10 + CDX with mares spares from my local dive center, used aqualung legend online, for around 320 I can get used aqualung mikron (maybe better suited for my wife) or used apeks flight. The used options all have been used for 100 dives or so. Our dive instructor strongly recommends us to buy new.
Anyways back to the OP:
If your looking to save money go used, honestly regs are such a simple mechanical item there is not alot that can go wrong with them if they only have 100 dives. I own 15+ regs and all were bought used never had an issue with any of them. Im sure there are many people on this board that are using 30+ year old regs. Also think about it if you use rental equipment this is probably the most used and abused equipment you can find so if your happy to use that why would you be concerned about a "used reg"
Also personally this whole "travel" reg thing I think is just a industry marketing scam to try and make an old product look new a shinny to sell more. Every reg is a travel reg, to me a "travel" specific marketed reg just means they made it with more plastic crap so it is "light weight" but plastic = braking. Even if you save 1kg on a plastic travel reg over something sturdy like a DST or MK25 who cares. It is 1kg. really in the grand scheme of things what is 1kg. Ill take 1kg extra weight any day over a plastic hunk or crap. plus your probably going to put the reg in your rolly bag carry on anyways so not like you have to worry about overweight check luggage.
As others have said stick with a reg that you can get support for. And if your traveling alot stick with the big name brands that you will find world wide. Think SP, Apeks, Mares. In this order these are probably the most popular brands you will see outside the US, especially in Asia, Africa, and EU