Really any reg can be a deco reg so if your pressed for money then just pick up an MK17 or MK11. If you have the money then sure get the MK25 to keep things simple and have everything the same as what you already have. The hose routing is a matter of personal preference some people hate swivels some love them so that is up to you to decide.
One major thing for you to consider since you live in Asia is parts and service. Since your in the Philippine I would say stick with SP since you already have MK25's. I lived in Asia for several years and still part time do and spend alot of time in Egypt and Europe as well. From my experience you can always find SP or Apeks parts at any tec diving destination in those parts of the world. Halcyon and Poseidon no problem in Europe but in Asia it can be tricky and as you know living in the Philippines trying to get things shipped to you is a mission plus tax is a killer unless your in HK. This was one of my main reasons I chose Apeks regs was availably of parts and ease of service in Asia, Europe, Australia, and Egypt. I would say SP is about the same. Also having spent alot of time tec diving all over those parts of the world I would say the vast majority of people are running Apeks or SP regs (with the exception of the US seems to be a lot more verity of regs being used there) and most are like me they carry alot of spare parts so you can pretty much count on someone having what you need if you don't have it or they are more than happy to help you fix it if you are not to sure.