I'm another relative newbie on here (been lurking for quite a while!), so I'm no expert, but I may be able to help regarding your room dimensions/screen size/seating position etc, as it is very similar to mine.
I have a NEC HT1000 mounted 11' from a 7' 16:9 screen and it just manages to fill the screen, so if you are thinking about a 6' screen at 13' you should have no problems. The AE300 has an even shorter throw, so will also be no problem, whereas the HS10 is quite a long throw and would have been unsuitable for my application.
When I demo'd the above 3, I thought that the picture on all of them was excellent, and at my seating position screen door was not an issue. The first to be ruled out was the Sony because of the long throw (which may not be an issue with the screen size you are considering) and also because it was too noisy to be ceiling mounted directly above my head.
So it became a straight choice between the Panny and NEC. The NEC did have a better picture, but not £1000 better (and I did spot the odd rainbow), so I was going to go with the Panny. However, I had heard the stories about Panny reliability (confirmed by the dealer, who said that they were no longer prepared to stock them because of it). In contrast, the NEC came with a 3 year on site warranty and a good reputation for reliability.
In the end I paid the extra for the NEC, mainly because I didn't want the hassle of ceiling mounting the projector only for it to keep breaking down. The added bonus is that I was able to mount it close to the rear wall because it vents out of the front and sides, rather than the rear, which seems to be the case with most other projectors.
Two months down the line I am convinced I made the right choice. Sorry for going on so much, but hope this helps you make your decision