What software are you using to edit? Lossless would be one way to go.
But video editing software is often quite compatible with raw 264 video streams and even m2ts straight from the disc (this obviously depends on the video stream and software). It might not be the most efficient, but any decent machine shouldn’t have a problem with an m2ts, and it’s quite convenient and small. If you need to render something in multiple stages, you’ll want to go with lossless.