I've been using inftekhosting to host my email for aprox 2 months now. I just wanted to go on record and let everyone know how great this service is.
I was specifically looking for a hosted Kerio account as I like the web interface much more then Exchange, but also needed the exchange features to OTA sync my (At the time Treo 755p) handheld device.
I've used it with the Treo 755p, HTC Touch, and now a Blackberry 8330. To get the blackberry to sync I did need to use a third party software package called Astrasync The people at Astrasync were amazing, I had some small issues and they helped me fast in their forums, and followed up via email. Once my trial was almost expired I licensed the product.
If you are in the need for a hosted exchange account at a GREAT price you have to check out Inftekhosting.