Ajmer is a good city, but only if you are interested in visiting the Dargah. There are no other tourist attractions that you would expect coming from Jaipur or Jodhpur. But you can go to Pushkar, which is an interesting place. But only if there is water in the lake. I wonder why there is no mention of it here.
The road from Jaipur to Ajmer is very nice and you can speed at 120 kmph almost all the way. If you are planning to stay, you should stay at Pushkar. Here the hotels are easy to find and much more equipped than Ajmer. At night, Pushkar can be very interesting. It's at a higher place, so can get cold.