You should check Phatmatik Pro, very simple and very fast.
1. open as a plugin in your DAW
2. open the loop you want in Phatmatik
3. click slice [ it's then mapped to your keyboard ]
4. change number of beats appropriate to your loop
5. and then drag the midi file from Phatmatik to your arrange page and you're done.
I've been using it for years, I've tried to find other stuff to do the same job but up to now nothing's done the job as simply as Phatmatik, it's literally job done in seconds.
You can get more involved if you want, change pitch, move your slice points around in real time, change the volume of each slice, filter it, modulate by LFO, distort, etc. if you want.
Great software and hardly anyone knows about it.