Pummel,
My information is a few years out of date now, so there may be some changes.
I used to keep my own aircraft at Seletar. Using club aircraft is just too difficult for regular flying and if you want any kind of flexibility, keep your own.
Parking is mainly outside (no free hangar space) but works ok in the main and is/was cheap. If you are on a foreign registration with the same license, it is pretty straightforward. As is planning and filing. VFR departures to Malaysia (Johor and further afield are very easy, IFR, perhaps easier still). Fuel used to be cheap (don't know now). Maintenance can be done at Hawker Pacific (but quite expensive, so be sure your plane is in good condition before locating to Seletar)
Some very nice and easy destinations in Malaysia, reachable without too much fuss, both mainland and island. Be careful of inland routes, as CB's build very quickly and reduce your options, however, offshore VFR routes are at inexplicable low altitudes way out to sea.
Best option is to file IFR, but fly mostly VFR on the lesser convective days, unless you have a very good radar.
Local training can be done on a very tight training area in Singapore, or better, just depart VFR to Johor (10-15mins flying) and do what you need to do there. Aero's not permitted in Sing, but ditto the Johor option.