On the numbers in this thread, it looks like the -500 had a usable payload of about 4.9 tonne, 52 punters and baggage would be a juggle. The numbers I have on the Brasilia gives a payload of 3.0 tonne for 30 pax. The Brasilia would go further on the same amount of fuel with a TAS of 280 kts and the ability to cruise above F250, As far as longitivity goes, I guess the F27 should last longer being a more solid aircraft, compared to the Brasilia. I understand some of the Australian registered Brasilia's are in the mid 30,000 hrs range and still flying. I would suppose the Saab's of Rex would be in a similar position