Ages ago, I thoroughly tested all the glucometers side-by side that were available in US market and came to conclusion that Bayer's Elite was better than others. Several years ago, Elite was discontinued and replaced by Contour. This one was tested against Elite only, not all the other contemporary competing brands, and was found to be equally good. From other colleagues I hear that many others are also equally accurate (or inaccurate). The advantage of Contour over Elite is that it needs far less volume of blood and reads faster (5 seconds). Less volume is particularly advantageous in mice work.
Besides picking the brand, look into the cost of strips - price of meters is not a big deal (in fact, our supplier often sends us a few meters every so often), its the strips where you pay. If yo find one brand cheaper than others (with comparable performance), go with it.
In animals there are specific glucometers for rodent glucose estimation this are the ones that give the best results. One human glucometer may not neessarily differ significantly from the other when used in rodents (sorry they differ significantly in cost). In my opinion any one would do for rodents if specific rodent meters are not available