The HTC Incredible S was launched in 2011, at the same time as the Desire S and Sensation. While this phone has made it to the Philippine via the grey market, it is only now that it is officially available in the Philippines.
The Incredible S is priced at Php18,000 which is about the same price as a Desire S. Both phones have the same internals, with a single core 1 GHz Scorpion processor, Adreno 205 graphics, 768 MB of RAM and 1.1 GB of storage expandable via a MicroSD card slot. The main difference is that the Incredible S has a 4-inch WVGA (480 x 800) display as against the 3.7-inch WVGA on the Desire S.
The larger screen and being priced at the same level as the Desire S, it makes little sense to buy the Desire S unless you want a smaller phone. Basically, I think HTC Philippines is replacing the Desire S with the Incredible S as their mid-level offering. This gives HTC a better phone to compete against the LG, Samung and Sony mid-level offerings.
The HTC Incredible S is priced higher than the LG Optimus Black, but it does have more RAM and the Scorpion processor and Adreno 205 graphics is a bit faster than the 1 GHz A8 Cortex and PowerVR 530 graphics on the Black. The HTC Incredible S also does have a higher resolution 8 MP camera with a dual LED flash. As against the Samsung Galaxy W, the HTC Incredible S has a larger screen and higher resolution camera. The HTC Incredible S is cheaper than the Sony Experia Arc S, and offers competitive specifications. The Arc S has a better camera though.
With Android 4.0 confirmed for this phone, if you budget is around the 18K range, I think the Incredible S is an excellent choice.