Getting split across multiple controllers is not a bad thing if you want to avoid corruption due to failed / faulty controller (I've got six controllers in my box, driving 12 disks).
If the controllers were the same type I would agree, but that seems to never be the case with these.
You shouldn't want controllers of the same type, no? That increases chances of data loss due to design flaw.
I am more worried about driver issues. For example on my hackintosh the SATA ports on the Marvel controller are extremely flaky. It may be that the fbsd device drivers are great for the various on board Marvel or Jmicron controllers you are likely to see but I still feel better using the known LSI driver.