I'm running a Fokker airline too. I love the things. I run over 50 F28s. Only recently once I firmly established myself as the leader in KDFW (I control the majority of all traffic through it) did I branch into A300s for dense domestic routes and DC-10-30s for long-range routes. I got stuck with a 12 TU-134s on short-term lease when a competitor went bankrupt and I had to swoop up some slots in a hurry with whatever I could get on the market, but those will be replaced with F28 Mk4000s soon.
Ironically enough, I got "stuck" with the Fokkers when, after the restart, I found myself unable to get the planes I really wanted. Instead of whining about the lack of planes, it prompted me to look around and the alternatives, and the F27/F28 are some really great planes for starting out. They're cheap to buy, cheap to maintain, cheap to operate, quick to turnaround, and you can buy them en masse with almost no waiting which is great for raking in as many slots as you can early on. I've even got a couple high-density routes I just run a lot of F28s on because they're honestly more profitable than putting an A300 on simply because of their efficiencies.
Next time I might try going with straight F27s to start, to magnify all the benefits of the F28 even more. Margins would be great with those since their costs are so low, it's just setting up twice as many routes 9as they're half the size) that'd be a bit of a pain.