I don't have an Epson 5020e but I can make a general comment on using a projector full time in a room like yours with so many windows.
IMHO, I don't think you will be happy with it unless you look to control the light more effectivly.
If $$ is not too much of an object, take a look at having automated blackout shades installed that will effectivly reduce the incoming light.
Adding the automation to shades is not much more than the shades by themselves (for decent ones anyway)
I used a Panasonic LCD for over a year as my main disply and you know what I discovered, I no longer cared about the size. I became too used to the large screen and then big movie nights were no longer "special". I have since moved back to a plasma for regular TV and use the projector for football and movie nights. MUCH HAPPIER! Everytime I start up the projector, I start to get a little bit excited again.
My 02 worth....