[BUFF]

don't know about the MSIs but between the abit IP35 & the IP35 Pro the Pro gains:
uGuru (best hardware monitor/fan control solution of any mobo manufacturer - also does overclocking in Windows)
2nd physical x16 (electrically x4) PCI-E slot
2nd Gigabit LAN
all capcitors are solid as opposed to just the important ones.
onboard power & reset switches plus external clearCMOS
different chipset cooling
slightly richer BIOS

probably forgotten something but you get the jist.
The extras are definitely worth something - the question is how much.
The price differential recently on SCAN's Today Only offers has been about £30 between the IP35 & the Pro version which is probably towards the top end of what the extras are worth to me (someone else may be different).