I think Microsoft will have better hardware and services, and I think Sony will have better exclusives. Microsoft doesn't have many studios or franchises I care about. A lot of that can change, but it's not like how it was.
To be fair, things are different for both of them. People, myself include, bought the PS3 for the potential we thought it'd have based on the PS2. Most of those big PS2 franchises came to 360, day and date. Even Metal Gear isn't exclusive and MGS4 was one of the big draws for the system...before people played it. So few third party exclusives these days that there's no real difference to these systems. Although, the rumor of Bungie's Destiny staying exclusive to the Xbox could be interesting if it pans out. One of the advantages the 360 had back then was being the only next gen console. Dead Rising, Saint's Row, GRAW, fukin Table Tennis, Fight Night, etc. made that first year great.
Me being dumb and thinking of it in this gens terms. Can't realistically predict how things will turn out from how different the PS2-era was from the 360-era.