If you’re paranoid about sanitizing the baby bottles, there are plenty of other options. For us, the best one was the microwave. For microwave sanitizing, you have two options: bags, or a tray. We started with bags, which they sell in the aisle with all the baby stuff. Basically, it’s a ziplock-style bag that you can put your stuff in, along with some water. Microwave the bag, and steam sterilizes your bottles/nipples/breast pump/whatever.
If the bags aren’t your style, you can get a tray-type thing, which is a domed plastic dealie that looks sort of like a Tupperware cake keeper. Inside is a tray to keep things out of the water below. Same deal as the bags: put your stuff on the tray and add some water, lock down the lid, and microwave for a few minutes. The steam (and pressure build-up) takes care of any creepy-crawlies. Both of these methods, needless to say, are a lot faster than running a dishwasher cycle, and it’s no sweat to clean the bottles out with a bottle brush instead of counting on a dishwasher to do the work.
Oh, and you can also get a dedicated tabletop appliance to do your steam sterilizing, but that’s expensive and just adds to your kitchen clutter. The microwave sterilizers are more than adequate.
Now, having completed that hijack, let’s talk dishwashers. The absolute #1 most important thing is: silence. Get the quietest one you can find. After that, it mostly depends on what you want. These days it seems that only the “builder’s grade” models have towers, so it shouldn’t be hard to avoid those. A stainless-steel interior is nice, but adds to cost. Most models in the range you’re looking at will have delay timers, which are also very good to have, and as mentioned earlier a front panel lock will come in handy when the little one starts walking (our 20 month old has already turned on the dishwasher several times, when my wife has forgotten to engage the lock).
Don’t be too dazzled by extras like a “china cycle” unless somehow you can imagine using it all the time. One option you might want to consider is the ability to run a “top rack only” cycle when you have just a small load; it saves water and takes less time. Also, check out how adjustable the interior space is; it’s very nice to be able to, for example, fold down portions of the rack for large pots, or snap out part of the silverware holder to make more room for dishes, or lower the top rack to make room for tall glasses, that sort of thing.
But first and foremost, go for silence. The less you notice your dishwasher, the more you’ll love it.