... If no loooong conversions are involved then I am about to purchase a hard-disc AVCHD camera soon...
That's the issue with AVCHD, including too many proprietary mixes -no single standard. PPro and other apps are only just now supporting that format, but it's processor intensive, and so much easier to just convert to "I" frame only mpeg transport streams (HDV), or cineform AVI's. I cutting a piece for a musician friend whom had someone else perform a four camera shoot of his concerto. Three of them in HDV, and the fourth, the main camera locked off on his piano was shot in AVCHD. What a PITA. 8-hours to convert in software and the result failed due to corruption. I'm now redoing this via hardware on my AJA board, now only 4 hours. (I'm sure that Cris is doing better on FCP).
In regards to hobby or home, AVCHD is ok if you can wait overnight to edit in something else. I shoot HDV to tape on Canons and when the warranties are up, I'm switching to XDcam on Sony. However, in lieu of AVCHD, at least for my workflow, it's much slower than sticking with tape and waiting for ingest.
BTW, cineform just announced support for direct conversion of the 5DMKII files if anyone is interested.