That's a great question, and I really love attending to these type of questions. The choices you have selected are pretty good and most of which are very popular choices. Keep in mind though, you're choosing the big wig providers. So their servers are robust, and in some cases the lack of attention to detail is included. All of those providers are by volume, whereas you go with a smaller, reputable provider. You might be able to squeeze more for your money and get the extra tentative to care in your specific needs.
First thing you need to do is figure out your budget. If you have done that already by dialing down the choices you've mentioned in your post, then that's a great start! If you haven't, lets work on that first. Next is to narrow down, what are your requirements are? Is a dedicated server over a hosting environment crucial or even right for you? Is it needed? I ask because more often than not, sometimes people buy more than what they need. Sometimes a VPS might just do the trick depending on the type of website your running, but I'll agree that with a dedicated server, you get complete and total control. What about your website traffic? What type of traffic are we taking about daily? Content? A mix of text and images? More of one than the other? Any specific functions? Plugins? How many plugins are active? Any that are known to have load issues? Security? Do you have any security requirements to be installed? Has there been any issues of any attacks towards the website like Brute Force attacks?
Without more information, some of the advice may not be helpful...and some will start to argue that advice. For instance, if your traffic is still within a certain range, then maybe a reputable VPS host would work. If your traffic or resource usage is beyond that, then a better solution is needed.
Uptime is important and it's good to find a host who takes that into account seriously. And I'm not just talking about the advertising mumbo-jumbo, but a company that stands behind that guarantee. I would check out each of those providers TOS/SLA fine print which is important when you are seeking 100% uptime.
Moreover, I think it's also important to look at how you will be rewarded when it comes to any unforeseen downtime. Generally with a 100% uptime, the data centers generally utilize a N+1 redundancy, from incoming power to outgoing data streams. This means that, when a system breaks, service is routed around the failed components to a backup without any downtime. It's important to make sure that the provider of your choice takes redundancy to extremes in order to mitigate unlikely disasters.
Now lets talk about speed. As this can differ depending on your location and not just the actual network. Most of the times, customers like to ping an IP address, with so many GEO location IP's going on right now and becoming a popular choice these days, it doesn't really say anything about the server speed. Even as such, downloading a test bin file. Thats your connection to the server, but has nothing to do with the specific server speed because it relies on your connection as well. Now when we look even beyond the complications brought on by varying connections, ping time tells you nothing other than how fast the given server responds to a ping. If you want to test, say, how fast a server will do a file transfer, the only way to do so would be transfer a file. A server that gives a ping request a high priority might look better, but wouldn't you rather be retrieving files from a server that gives a high priority to ftp requests?
At least with most of those providers in your list, you're going right to the source of the servers so you'll likely get the uptime and in some cases the speed you desire. Hope that helps!
