There are several things that are going to push the cost in one direction or the other for an entry level hybrid. Probably one of the biggest is whether the brakes are hydraulic or mechanical. If possible go with hydraulic. There will also be a difference in wheel quality, but at these prices you're splitting hairs. Again, an $800 bike is pretty much going to be the same across the various manufacturers. Also, keep in mind that you're going to spend about $150 more per bike after you get done buying a few essentials like a helmet, pump, patch kit, saddle bag etc. If you have a Trek dealer nearby I would just get in line, tell them you and your wife are looking at Trek Hybrids and have them let you try a couple of different sizes and find one that fits. If you want a particular model that they don't have in stock just ask them to order it in that size for you. Or, since you now know your size you can call another Trek shop and ask them for that model and size, and curbside delivery.