REC vs QCell

Hi, I’m looking into solar for my brother and we’ve narrowed our panel choice down to either REC 315w Twin PEAK split cell or Q Cell 325 Duo split Cell.
REC appears to offer better warranties however the company tells us the QCell panels perform better and they sell more of these than REC.
Any insight on what would be the better choice would be greatly appreciated.
The system quotes are:
8.19 kw REC and Fronius 8.2-1 with smart monitor $8,190
8.45 kw QCell and Fronius 8.2-1 with smart monitor $8,310
Thanks for any feedback
Westley