The ren is a good buy depending on a few factors: 1. Do you already have a good audio interface? If no, the mpc ren is a good buy since it is also an audio interface. That is why it costs a bit more than maschine. If you don't need the audio interface then go with the MPC studio which costs the same as maschine.
2. Do you know/prefer the MPC sequencer/workflow? If yes, then it is a good buy. It's a good step for DAW usage for guys whonhave spent years working on MPCs and have countless MPC program files/sessions/samples on disks. It's an easy transition for them.
3. Do you plan on investing heavily into NI products? If no, then look more into the MPC. If yes, look more into Maschine or some other midi controller because you'll be able to integrate it more with their plugins.