The evo shift is a good phone, has an official cm7 build, and has a slide keyboard for those who like it. Not the greatest battery life, but that is the biggest failing in my opinion. Obviously running a custom rom will greatly help that. Do not get the marquee, as i think at phone has been discontinued already. Check sprint.com for that. Any phone they do not sell on their site you do not want.
Edit : okay i swung by sprint.com and they have the marquee marked as out of stock. Check the android central forums to hear peoples frustrations with that phone. Thry have both the evo 4G and the evo shift as a free upgrade right now. I would likely choose the evo 4G as it is largely the same as the shift but slightly larger screen and again has an official cm7 build.
Edit again : okay a friend suggested that as it is what he just did. Tigerdirect.com has the motorola photon for 49.99 with a renew/upgrade. I dont have any personal experience, but thought i would throw that out there.