I have an account with RZ and they have been good. Now due to the limit that they have imposed which regards to the hostable domains (yeah that was long ago), I am thinking of either upgrading to a larger RZ plan (to host more domains) or to switch to JaguarPC since they offer unlimited domains with overselling.

Both of them offers $19.95/mo. JaguarPC offers more features than RZ for that price. Now if you think i'll host millions of domains on it and abuse it - NO. The reason is that most of my hosted sites only eats 5-10MB at most and the limitation gives me a lot of unused resources. I feel JaguarPC suits my needs, do you recommend them?

They've had a good reputation around here and, if RZ isn't willing to do the unlimited domains, then it may be in your interest to switch. However, sometimes its a lot easier and wiser to stay with a host that you have had experience/dealings with for some time.

there are actually quite a few threads lately comparing the two of them