Verified answer

TL;DR version:

The system's hardware sets the maximum bar for gaming, but it is up to developers to push the games up to that bar. Developers will only spend the money and man-hours if they foresee a profit and the 360 has a larger consumer base for larger potential profits.

Verbose version:

Hardware might attract developers if the developer has some idea which is not easily performed on other hardware.

However, software is what attracts consumers.

Microsoft was very aggressive about attracting developers to their system whereas Sony more or less rested on their laurels of the PS2 era and hoped that impressive system specs would attract consumers.

The wii is extremely weak in terms of hardware. It is virtually two GameCubes strapped together. It has the same processor architecture running at twice the frequency with double the RAM. However, it was blowing the PS3 out of the water for a long time.

This has caused a few cross-platform games to sometimes look less than optimal across several systems due to efficiently porting the same software to different systems to reach the maximum audience to get the greatest return for their investment. Sometimes, they stress the lowest performer (wii) leaving the other systems idling. Also, sometimes there is an original targeted system and the code is lazily ported to other architectures which shows in the end product with lower texture resolutions, slowdown, lower polygon count models, etc.

Since the PS3 is not as popular, it rarely is the primarily targeted system.

For example, rune factory is on both the Wii and PS3. Although it is a great game, it looks graphically very weak on the PS3 and sometimes even has slowdown and frame droppage. This is most likely because it was developed for the Wii and ported to the PS3.

Regardless, the Cell processor in the PS3 is slightly better than the processor in the 360 having 6 single threaded cores available to the game (7 overall, 8 on the die) with a double-threaded PPE shared between OS and game as well. This is opposed to the 360's 3 double threaded cores (split between OS and game) in the 360's Xenon processor. From what I've heard the graphics processor in the PS3(RSX 'Reality Synthesizer') is somewhat weaker than the 360's Xenos despite the RSX being superior on paper, but that's hearsay of unknown truth value. Both processors are related to the Power PC architecture, but the 360 is supposedly easier to program.

The PS3 does have somewhat more of connectivity options, but I'm guessing you weren't including that in the "advanced and powerful" portion of your question.

Rey are equal to me in my opinion

Because x-box has kinect.