LCD still has issues with fast motion scenes and screen door effect. As well, native contrast, without an iris, is inferior to LCoS technology.
Once UHD resolution has really nailed things I expect that I will really be on board, and I think that all the Epson models are pretty darn solid. I'm just not sure I would spend an extra dollar for the 5040 over the HW45ES at this time.
Now, 3,500 lumens is a ton of light output, but I've used 300 lumens and had a very good image with some lights on. So, a ton of light isn't really what I would be going for. Contrast, color accuracy, image processing, and image accuracy are king. It isn't giving up light output if you don't need that light output to begin with.
Motorized lens presets is phenomenal if you have a 2.35 screen and need to switch. I'm a huge - HUGE -fan of that. But, if you just have a 16:9 screen, it's not worth any extra really. You set your lens, then leave it be for ten years.
There is no content with 4 million pixels. So, it is either throwing out 4 million pixels from UHD, or scaling up 2 million pixels. The fact that it supports UHD content though is a huge thing because the content itself likely is of significantly higher quality from the start. Just like watching HD content on a 480p TV back in the day was night and day better than watching SDTV. I don't think the jump from 1080p to 2160p is night and day, but I think the original source will be better and that will translate to the projected image nicely.
So, there are some advantages and disadvantages with both the Epson and the Sony, but I'm cheap.
Heck, right now I run the BenQ W1070 which is under $1,000. Not even close to the Sony or Epson.