My scenario has been different. But at the end of the day I, too, found Disk Utilities RAID functionality too problematic to use.

I have used two Seagate FreeAgent Pro disks via FW in a RAID 1. The problems I faced were that
a) the RAID would break (for whatever reason, I could not reproduce, but it happened ca 3-4 times in ca. one year)
b) it actually broke without warning before mounting the single disk: no error message
c) it continued to operate without warning that it is running one disk alone: e. g. no changed icon in the finder
d) Disk utility took very long to restore the RAID, ca. one day for 1 TB, whereas typical transfer rates to either drive and the RAID were much higher. Needless to say that I left the Mac and drives alone while restoring.

I finally decided to break the mirror and use two separate disks and a different backup strategy. Alas, another problem arose:
e) Breaking the mirror via Disk Utility left the two disks with the same device id (UUID), which caused all sorts of problems when the two disks were mounted simultaneously.

So the best I can say re. b) and c) is that the mirror worked in that upon "failure" of one drive the RAID continued to function. Too bad that the drive didn't really fail.

And yes, I have filed bugs for Apple.