For the major brands, bicycle models at similar prices points are going to be close in quality. (Specialized, Trek, Giant are good brands.)

I'm assuming you are talking about them.

Sirrus Sport

http://www.specialized.com/us/en/bc/...8&menuItemId=0 $710

Trek 7.2fx

http://www.trekbikes.com/us/en/bikes...ss/fx/7_2_fx/# $549

Giant Escape City

http://www.giant-bicycles.com/en-us/...11/6963/43123/ $540


Some differences between the two

The Trek has lower gearing (better for steep hills) and wider tires (more comfortable on rougher roads).

The Specialized has a some-what nicer rear derailler. (The specialized list price is a bit higher so that might be expected.)
The Sport comes with a carbon fork (which might be a bit more confortable than the steel fork on the trek).

The Escape City is similar to the Trek but it comes with a rack ($40) and fenders ($30) (which you would appreciate if you plan on riding in wet conditions).

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You should carry a pump, spare tube (or two) and tire levers (and know how to replace them).