If carousel or not depends on your aims and what reagenses you want to use. On carouseltypes you can use any reagens you like to. The tissue-baskets dump into the liquid for the programmed duration.
With the chamber-type there are some restrictions on reagenses, that are not likely to explode ;-). They have the advantage of a closed system, and that you can infiltrate with vaccuum and pressure. Also the chamber can be heated while fixation and dehydration, what may decrease your processing times.
I cannot say much about the various chamber types, but in my lab the VIP has been used for years without problems. The new models have some features like counting the runs, warning for reagens change, etc. Some instruments also measure the ethanol-content (how many percents) and change the reagens automatically. Some advertise with the possibility of using xylen-substitutes.
In routine histotechnique it's also important, that the following equipment is adequate. I think of baskets, that fit into the embedding center.
hope this helped a little bit