I have a 5-dr Facelift with Mag ride. Love most things about it, just a bit soulless which is hard to quantify.
I love the sound, but it's not as nice as my old T5 Focus ST - just not enough popping on the over-run for my liking. The handling, as said really, it's a bit detached around the helm, basically a lack of steering feel. There is tons of grip from the AWD, but you really have to trust that the car will stick rather than feel whats going on. I don't get any bounce or lack of body control that seem to affect the non Mag ride cars, so it's a worth while investment I think. The body control is actually really impressive, stays very planted but the ride is generally very firm and harsh, even in comfort mode. The bumps don't tend to hit the cabin much mind, so it's isolated very well but you kinda feel it through the movement. If you can get it to under-steer in dry conditions on the road, the you are going 'way too' quick on a public road and need to be having a word with yourself. In the wet, yeah, it will under-steer, but no more than any FWD car... you can get power over-steer on exit of junctions and roundabouts, but not in the dry.
Gearbox, is a funny thing I've found. It's hard to get on with coming from a manual, but I think that's more me, than the car. I'm expecting it to do everything and straight away, where as I look it now with a more realistic view. Plant your foot on the floor and it has to drop down some cogs and there's hesitation as it decides what to do, but then, if it was a manual, I'd be dropping the clutch, changing gears and then back on the power, so get the same disruption. Same process, less effort basically.
I do find there's too much dead peddle on the throttle in anything but 'S' mode - that annoys me.
Interior wise, it's a lovely place to be. Standard MMi is better than what you're used to from the Fiesta, but not as good as some of the touch screens out there like the one in the Seat Leon. I use Apple CarPlay most of the time anyway, so I can live without it being brilliant and I'm just learning it's menu's now. Virtual cockpit is great, B&O sound system is awesome, Super sports seats are nice to look at, just wish they were abit tighter (S4 versions have adjustable bolsters!).
I terms of options, I really like the light bars in the doors. Hill hold is worth the £75 they charge (should be free) and Adaptive cruise control is fantastic! If you're going to be sat in traffic or do a lot of motorway miles, it's a god send.
MPG and running costs are okay, probably won't be much different to your Fiesta ST actually. I get around 29-32 mpg and 320-360 miles from a tank. That's with a proper mix of roads and some fun driving aswell, so pretty impressive. I've had 422 miles from a tank once!
I wouldn't remap it if you value the warranty - wait til it's out of that if you want to play with it. I hope that helps
In summary, a damn good car. But won't be as exciting as your ST200 to drive, but nicer to own.