Marius is of course right - You get full root access and the ability to do whatever you want. From a customer perspective (Marius works for Solar) it means that you can pretty much treat your VPS as your own server. Do as little or as much as you want to to it.
As for the "administrative panels" as you call them, there's 2 levels of those:
Each VPS comes with Parallels (formerly known as Virtuozo) - This is the top end panel, for want of a better title, and allows you to stop/start/restart your VPS, view bandwidth and resource usage, QoS alerts, yada, yada. Every VPS here comes with this panel as Parallels is like the shell within which your VPS runs - Within that your VPS has the O/S you've chosen and full root access. PuTTy is your friend
Besides that, you can then choose (or not) a control panel which are more designed to run web site hosting, mail and FTP services, etc - They take away the need to be a command line guru and, if you're wanting a VPS to host web sites on, a control panel takes away a lot of the command line stuff and lets you concentrate on the web sites etc.
I just took a quick peek at your blog and you seem to be a bit of a wiz with this stuff already so if you don't want a control panel don't get one. Bear in mind, though, that no control panel also means no management services (common throughout the VPS supplier industry) so you're a bit more on your own with troubleshooting etc. WITH a control panel you get the full clout of the Solar Support Team (including Marius!) who, in my humble opinion, are just about the best (technically) and friendly bunch of gurus you could ever wish to have on your side
Whatever route you decide to go, don't worry - Team Solar tend to do more than it says on the box for their customers, and you can always change plans and options later if you feel the need. I've been with them more than a year now, with VPSs on both sides of the pond, and I ain't planning on moving anywhere else anytime much before hell freezes over (and I've tried the other places, and still have the scars to prove it LOL)
Welcome to Solar - Enjoy your stay!