There isn't and won't be any SP component because the industry hasn't figured out how to fuck over gamers with microtransactions within a single player environment.
As for the MP, the free to play model in this game is pretty dire. Any half decent F2P game will start everyone on an equal footing and then provide advantages to paying customers that don't affect game balance. MWO is not like that. As a free player you will start in a clearly inferior training mech and you will have to grind for hours before you can even afford to buy a somewhat competitive mech. And even then the game has way too much grinding in general. And performance is not where it needs to be. Big open maps though, thanks to the Cryengine 3. It's open beta now, so everyone can give it a shot to see for themselves.
Some of the most miserable and unhappy gamers on the planet are at Bluesnews