Making the right choice in your quest for a VPS solution for your WordPress blog is a case of weighing up the benefits (such as speed, bandwidth, storage space and any included support) with any detriments, such as an unnecessarily high monthly fee.
Moving to a VPS should offer you an improvement on all of the above:
Speed – You should be looking for a package offering at least 1 GHz of dedicated processing.
Memory – Go no lower than 512 MB.
Bandwidth – Unmetered options are available; choose a package that offers more than you were previously using.
Storage – Your website/blog is going to keep on growing, so select a storage option to allow comfortable expansion.
Support – There are hosts out there that will expect you to understand Linux and connect to the server via SSH to set it up and offer support for doing this. Avoid these unless you have a competent expert that you can call on.
You should also be looking for a specific server type. For the best results, you will need a LAMP-based server (Linux, Apache, MySQL, PHP), as you may find that some WordPress plugins don’t run too well on a Windows servers.