ServerBeach and TP are both known for offering low quality dedicated servers... why particularly those rather than one of the higher quality providers?
If you're getting a dedicated server then the most cost-effective way is to buy/lease-to-own and colocate it. That way you pay far less and know (at least in terms of hardware) exactly what you're getting.
However, I'm not sure I'd recommend a dedicated server as the best option for most people - even when you have a few sites it isn't necessary for most people.
If you can't cope with moving from shared provider to shared provider who isn't offering the quality you want - pay more and go with a decent shared provider, or get a decent VPS...
In many respects the VPS provider can't cause you problems to the same extent as a shared provider - particularly if it's self-managed, as you pretty much rely on them for network/hardware in almost the same way as you would for a typical rented dedicated server (but without the huge cost).
A VPS is much easier to upgrade too
