I wanted to migrate to GNU ("Linux") for years, but could not because of the lack of some programs or functions in programs. This changed with one of the recent versions of "Openoffice". So I looked for the last thing to make me happy: A video cutter.
And I found it! Of 2 acceptable Linux Cutting-Programmes, one, Kdenlive, was supporting the .m2ts-files of my camcorder. Voila!
Then I needed some time to install it, because the installation via Ubuntu, Kubuntu, Mint or however you call it only works with two additional lines in some configuration file, and it took a very long time to google for that. In the end i found it, but not on the Kdenlive site.
Ok, now it finally worked! Heureka!
BUT:
a) if you want to open .m2ts-Files, you have to select "all files" first, because it's not one of the "supported" filetypes.
b) finally you can import .m2ts-files. But the PREVIEW is SLOW like a snail!
c) trying to click something in the clip-window nearly freezes the system
The additional problems are
1) Simple preview only uses one core
2) There is no native GPU-Support
3) Working with Proxies does not work for me
I don't say that all those problems cannot be solved with some tricks. But is the user, that migrates to a GNU-System, really expected to do all that things, inform about bugs, learn to compile programs for broken dependencies, install the vdpau-version of ffmpeg and risk instability, etc. just to cut his HD home videos?
Not even simply buying the latest hardware solves all that problems, because the only solution would be more MHz, and in CPU-production they go other ways now because of physical reasons.
HD is not future, HD is real now. And the support of .m2ts is not given only by letting slap that files onto your timeline, but by creating an environment that works fine with those formats.
Not only to do bad critics, I love Kdenlive. And I'll wait for it, until it meets my cams requirements.

I have to add a few things.
1.) Yes, I am a GNU noob, and all what I was saying is that Kdenlive is not HD-ready for noobs.
2.) Yes, I am working on a 64-bit-system, which is installed extra for kdenlive. So if there is a "driver tohuwabohu", that would be a failure of the Ubuntu project. And no, as a noob, I am not ready to compile my whole GNU system for myself.
3.) Now, tell me, if system requirements rise, where will Kdenlive go? More MHz will not be the future. This is a very interesting question for me.
As mentioned, I repeat that it is possible to get kdenlive HD-ready. But not out of the box.
I am definitely not complaining. But I want to do constructive critics, by asking, how I can recommend GNU to other friends, when after installation of the new, user-friendly releases like Ubuntu everybody tells you "no wonder, that nothing works, you didn't compile your whole system for yourself!".