I have posted it before many times on the mobile forum.
Both videos, pics and reviews.
And as you can see, you seem to be the only one here who thinks that and in fact you are the first person I have come across from all the forums/websites I browse where I have seen someone saying that the sensation has a better screen for view ability in direct sunlight.
Maybe you just have a special mobile were every thing is perfect
Just simply type sensation VS GS 2 sunlight or something like that and you will see for your self.
Here is a few that I quickly just found:
http://www.phonearena.com/reviews/HTC-Sensation-vs-Samsung-Galaxy-S-II_id2766
The LCD screen on the HTC Sensation appears a tad brighter indoors, but outside under direct sunlight the very low reflectance of the Galaxy S II coating makes the image slightly easier to see. There is one area where the HTC Sensation is ahead, though, the 540x960 qHD resolution, compared to 480x800 pixels in the Galaxy S II's 4.3-incher. Since the Super AMOLED Plus technology gets rid of the PenTile RGBG matrix pixel arrangement, the individual pixels are not distinct as on the Galaxy S, for example, when you bring the phone close to your eyes.
http://androidcommunity.com/samsung-galaxy-s-ii-vs-htc-sensation-video-20110520/
Outdoor viewing goes to Samsung though by a mile.
Both explain it a bit different, but at the end of the day they state the GS 2 is the better one and there are many more user reviews etc. out there stating pretty much the same thing.
Plus I have used both in sunlight and to me the GS 2 is the better one for being in sunlight.
Even mekrel who really wants to prefer the sensation over the GS 2 says that it is better.
EDIT:
To quote from anandtech:
Maybe that is why then it seems better for you compared to the GS 2.
Also I can't see them not properly comparing the sensation to the GS 2 screen.
The SAMOLED+ is much better than the original and they would obviously have both at hand to properly compare and not just assume, especially one the big main features being the arrangement of the sub pixels, they just simply wouldn't do that.