XL1? Don’t worry about it. I capture to my MBP’s internal drive all the time, and have never had a problem. I did get the 7200 rpm drive, though, just to be safe. I do realize it may not be appropriate for HD throughput, but we’re talking DV25 here.. I don’t know why everyone freaks out about it.
I do a lot of field production and it’s great to have it right there without the hassle of extra drives.
Zero issues for me, YMMV.