Congratulations!
You are gonna love the Citation. Cessna basically makes 1 type of airplane....a C-172. Then they just vary it slightly, different engine(s), bigger cabin, etc. (You'll see what I mean, LOL!) But seriously, the Citation 500 series is the best first jet out there in my opinion. It's easier to fly than most of the bigger twins out there (C-421, Navajo, King Air, etc.). You only have 2 thrust levers to deal with, all the systems are very simple and typical Vref (landing speed) is around 100 knots. Single engine is no problem, kick in a little rudder and just keep on climbing. It's a very forgiving and flexible airplane....I've done 250 knots to a 4 mile final, and comfortable crossed the end of the runway at 100 knots, don't try that in a Learjet!
It may be a little slower than most jets, but it was never designed to compete with a Learjet, it was inteded to compete with a King Air. Compared to the typical King Air, you will cruise 100 Knots faster and 10,000' Higher, all at about the same operating costs per trip. Even compared to a Lear for example, most trips will take you only 5-15 minutes longer, big deal. Short field performance is great, I've used 3,500' runways with no problem, you won't do that in a Learjet either. Roomy Cockpit with big windows.
Citations are perfect airplanes for trips with a few passengers for up to around 1000 miles. Beyond that you probally want a midsize jet for better passenger comfort. The only real difference with the S/II is the "weeping wing" anti-ice system instead of de-ice boots. This system, from what I understand, is much more of a pain in the ass than it is worth. Boots are good, I probally only have to blow them a dozen times per year...and the airplane handles ice very well.
I can't think of much more to say right now, other than you will love it. By the way, I don't mean to rip on Learjets, they are great airplanes too. But the versatility of the Citation is outstanding.
Have Fun!
JetPilot500