When you say you are looking for a computer, I assume you mean a cycle computer, not a laptop.
Mine is from a company that is no longer in business, so there is no reason to mention brand. It is a base model that gives; average speed, max speed, time of trip, distance of trip, odometer, can custom calibrate it for wheel circumference. The thing I like the most about it is that it has a robust wire that does not break if you accidentally snag it. I previously owned a number of expensive cycle computers that stopped working each time I snagged the wire on something. I tried a wireless one on my foldup bike and decided I prefer a wired one over wireless.
Some people prefer a single unit that does everything except make the morning coffee, but I like to have a computer that is separate from my GPS and separate from my heart rate monitor.
If you have a choice of mounting on the stem or handlebar, that gives some flexibility if you have a lot of stuff on the handlebar. Example in my case, if I remove my handlebar bag I can fit a light on the handlebar but if my computer could not fit on the stem, it would take up valuable handlebar space.