I suggest you only for searching and try find only best company because you need great support and great stuff if you wont that your clients stay on your server. What ever you done, doing, make , make with quality and create better stuff then competition.
I use BurstNet. They're great actually. Btw, the BN in my username does not relate to BurstNet in any way.
Just go through reviews of those and the major question is that what technology based server you want to run your sites ?Choose only that which is good enough with that technology.