Beware VPS myths!
A VPS does not necessarily have better/faster response times than a reseller account. That's a myth -- often one created and perpetuated by the VPS hosts, not actual independent tests or end users.
One of the benefits of "reseller" hosting -- again, really multi-domain hosting, resale not required -- is that you don't have to manage your own VPS.
If you've not yet read this, you really should
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The Myth of VPS Hosting: Reasons to Avoid It! Part 1
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The Myth of VPS Hosting: Reasons to Avoid It! Part 2
Best VPS hosts
If you're deadset of a VPS, then other exllent VPS hosting options include
- Arvixe
- WebhostingBuzz
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Namecheap
- Site5, which you already use for reseller hosting, so you should be familiar with them
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Veerotech
- Stablehost
Namecheap and Site5 have "no root" managed plans. The Site5 managed plan is a bit pricy, but you get what you pay for -- as you've apparently already discovered with Digital Ocean and RamNode.
The above hosts use Xen, KVM or Hyper-V, which are the best virtualization methods. You'll run into less issues. RamNode was an OpenVZ host, and OpenVZ can be a big PITA.
If you don't mind using a Virtuozzo host, then
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Knownhost, which you're already usede -- curious why you did not like them?
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WiredTree
- FutureHosting
In general, Virtuozzo (commercial OpenVZ) is not great, but these hosts do well to monitor their servers. Issues are therefore far and few between with them.
Half of our audience is USA, half Europe, and we use
EuroVPS -- no complaints on either continent, as far as site speed goes.
Reseller hosting = might be ideal
Unless you're doing something special with the VPS server caching (Varnish, memcached, APC, etc), or want to allow the CPU/RAM use to just do whatever it wants (not good!) instead of regulating it with CloudLinux, then I still think a quality reseller plan is your best bet. Site5 is a good host, but the reseller limits tend to be somewhat tight, so I think
Veerotech or Arvixe would be a better choice for you.
It just really depends on how much you want to micro-manage the sites.
I've been a server admin since the 90s, and tweak everything as optimally as possible. Even VPS is often not enough -- I needed dedicated server to control everything. But it takes lots and lots of time. Managing a server can take just as much time as managing a site. If you're doing it well, that is! (Poor server management = hacking issues, hardware issues, software issues and more!)
I'm not trying to talk you out of a VPS, but you need to know what lies ahead if you go down that path.
WordPress cache options
In terms of cache, Super-Cache is outdated junk, and the W3 Total Cache (W3TC) plugin is so bloated that it doesn't heko much as a result. The best WordPress cache option is using both
DB-Cache Reloaded Fix and
Hypercache Extended. Use them both together, and if your site load times are not 1s or less, then you need to look at your page bloat (large images, etc) with a Pingdom page speed test.
http://tools.pingdom.com/fpt/
WordPress security
Plugins are mostly useless. You can't protect a system from within the system itself. That's like having the castle moat in your throne room. You need to the moat outside the castle!
This is where a VPS will come in handy, although some excellent shared/reseller hosts implore various security as well.
You need to leverage Varnish and mod_security to keep out the junk traffic. That's just for WordPress, in addition to a good server-wide firewall like CSF. Each of these works in different ways. This post isn't the place to go into this in depth. In fact, some are rather new, and I'm still currently adding them to our own servers. After which, I'll write some guides to share with other server admins. But it will be a while.
It's NOT easy to do -- I'll say that. Even I'm having some issues getting mod_security rules set. Previously, I'd tried fail2ban, with some success, but it was not working reliably.
I discuss security with several hosting owners frequently. Some of us are very proactive.
For Varnish, the commercial cache plugin from Unixy is best. Manual installation of Varnish is not fun at all. You can either buy an owned license, or lease it monthly.
CloudFlare = avoid
CloudFlare usually slows down sites that are on good server. It doesn't speed them up. That's a myth. Only if the host is really overloaded and terrible -- think Hostgator (EIG), Godaddy, etc -- will it help.
The "security" is also somewhat crappy, and often blocks legitimate users from visiting your site. You can secure your own site much better, so that it ONLY blocks junk and not legit viewers.
I would avoid that mess entirely.