I currently have one account with Crocweb, they are really good provider.
Their ssd is very fast(at least for what you can expect for reseller), and support is answering tickets almost instantly.
I did have a few short term problems, but they were solved very quickly.
I've heard about both companies you've mentioned before but I've heard a little more good about croc web than dream host. Take in mind dreamhost does have a custom control panel and it can be difficult switching to another provider in the future.
I've used CrocWeb before and I enjoyed my experience with them, great support and uptime. I can recommend them, I also recommend FreshRoastedHosting.
We have a few special-needs clients hosted on a CrocWeb account, and we're very happy with the service. There's currently an outage affecting some of their customers, but that can happen anywhere.
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Not to resell hosting but to separate all my sites I host.
This is not possible with Dreamhost. They do not offer a reseller plan like you're thinking. You would be able to separate the domains using different ftp users (user x who controls xxxx.com will not see the files for user y who controls yyyy.com), but all domains/mail/mysql/etc would be housed under the same (proprietary) control panel.
We do our main VPS hosting through WiredTree, which has been great so far. Just opened up an account with CrocWeb last week for some other lower-priority sites, based on strong feedback on WHT. Unfortunately they've been down more or less constantly for the last 18+ hours, which is the longest outage I've ever experienced anywhere. Planning to take them up on their money back guarantee once their site is available again and look elsewhere.
Dreamhost is one of the best shared hosting services i have used. It's true they use a custom panel but it is easy to use.
As far as moving to a new host, this can be easily achieve by backing the database and the files and edit the config file of your script.
Most of the major hosts, ie: hostgator practice that. Its certainly better then having a server down for 30 hrs which is completely unacceptable.
Good luck doing that when all of your IPs are being targeted with 40GB+ attacks and your datacenter null-routes them for 24 hours. We have over five hundred IPs. They were all being targeted constantly. The attacks would return even after changing IPs.
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