QFX5k question

Hey there, I am trying to get my hands on some QFX5000s and I have a rather quick question. In the past, I often used MX + EX where MX did routing and I connected all uplinks/peering and EX, and EX did switching, i connected my servers to ex. in QFX, I am trying to see if I need EX or not? more importantly (besides from what juniper papers say) are there any known issues people run into for a small scale deployment. (100mbps-1gbps range 1 rack, 20 servers) my plan is to have QFX to it all, but i am worried, if this is too much for QFX, if you have relative experience on this , feel free to let me know thanks in advance mehmet