There is a OnePlus 3 discussion thread in the android sub-forums where it includes the discussions of 3T too. Anyway, as you mentioned, it packs great specifications for its price tag, it's among the top few fastest android phones I've tested. Software is nice and clean. Hardware is pretty much top of the line still. Only the lacking a bit in camera department (still good, but experience not at Samsung, Apple, or Google level), and no water resistant. But considering the price, not deal breakers.
Just note there are 2 variants. A3010 which is China set. A3003 which is Global set. Global set will support the faster 4G+ speeds here in SG while the China set is just normal 4G. Both can use. Also they're both Without official warranty of course. Some sellers do offer warranty services (help you shop back for warranty) for like a month or so like Expansys, with options to extend.
If no hurry can always wait for qoo10 to have coupons to buy the phone. I normally would recommend expansys since they're quite well-established and have been around for a Long time already. Sometimes can get it under 500 for the A3010 variant. If you want A3003 be prepared to pay a lot more.
