There are less expensive choices. The entry level Trek FX is $359 and the entry level Trek Verve is $399. You might find them even cheaper on sale.

I wouldn't badmouth the Diamondbacks. My son is still riding a Diamondback Parkway purchased in 1999 with over 15000 mi. Chen components and all... Shimano Acera or Alivio drivetrain (can't remember and the bike is not handy...).

All it takes is to learn to do the basic adjustments (Park tools videos in YouTube) and it runs smoothly. My wife's Gary Fisher Nirvana (same age) shifts crisply with its Sram Gripshifts and middle of the road Shimano drivetrain (no 105 or Deoore there). I spent half an hour adjusting the drivetrain 3 months ago (when I changed the chain and 8 speed cogset) and runs smoothly. She resists buying a new bike because she likes it. I have to say that she looks like she rides IN the bike, not OVER it, like the olden days bikes looked. Like a cyclist should!

In some areas, CL might net you a decent FX or Specialized hybrid for $300, 2-4 years old. If you find one and it fits,.... buy it. Fit is the question in the used market.

Good luck.