PS3 Blu-ray loading times are just fine thanks.
The problems with Microsoft being involved in the media format war, is their viral marketing droogs have littered forums with mistruths.
Here is some facts.
1. The 360's DVD drive is quoted by Microsoft as being 12x. However, here is the first catch. That is ONLY for single layer discs. with DVD9 dual layer, it's actually only 8x.
2. The 360's DVD drive is CAV, which means the data transfer rate varies across the disc surface. Microsoft of course, quote the fastest, 8x (88.8mbps), on the inner of the disc. At the outer, it's closer to 4x. (44.4mbps)
3. the 2x Blu-ray drive in the PS3 (used for both movies and PS3 games), use CLV, delivering constant data transfer rates across the entire 50GB of the disc. (72mbps)
As you can see, the 360 is marginally faster for a very small part of the DVD disc. It can deliver about 1-2GB of data on a DVD faster than the PS3, however, the PS3 can deliver the full 50GB of data faster than 90% of the 360's DVD.
In the real world applications, and certainly with the current multi-platform titles, there is little to choose between PS3 and 360 load times, unless of coarse you use the standard HDD in the PS3, in which case, unless the developers have royally screwed up, the PS3 will always have much shorter load times.