Trek has produced the 520 for years. Comments have been weak rear rack and not low enough gearing. I am turned off by the Kona by the high front rack braze-ons. Front rack bags should be centered on front axle for maximum stability.
Not low enough gearing on the Trek 520? Bizarre. It comes from the factory with 26x32 low gear. Fairly low. It has a crankset with 64mm bcd inner chainring. So tell the bike shop to put a 22 tooth inner chainring on it before you buy it. Easy. 22x32 is low. And you could also tell them to put a 11-34 9 speed cassette on it before you buy it. 22x34 is very low. You can also buy these parts from Nashbar for $34 cassette and $16 chainring. $50 for super low gearing. Can't complain about that. Kona is the same gearing as the Trek. So do the above to both bikes before you buy them.
Kona does have a high front rack for some reason. It has two holes for bolting the rack on the fork. Picture shows it using the lowest hole already. Guessing Kona believes this is a semi mountain bike. Have heard mountain bikes have high racks for clearance off road.