I would definitely look too, I just spec'd a new X1 here (the new version can be ordered and configured already) and the price is a little higher, nowhere near the difference that the folk in the US talk about. I really don't know where the idea of turbo petrols not being able to run high mileage comes from. My last 2 cars were 1.4 VW turbo and my dad had a seat 1.4 turbo. Plenty of power and good torque, sold them all about 80k miles, my Dads was over 100k miles, standard services nothing special. They are as common as cheese here.
I was thinking of holding off for one, but the fact it is my wifes car, she loves driving the Mazda and having a nice set of winter alloys and tires I could use if I bought another Mazda made it much less hassle.
Both engines you mentioned would be very nice, I had a company car for a few days, 1.8T Audi A4 avant, 180ps, was a peach of an engine, pulled like a train, very quiet and economical if you kept your head, I would have that engine again anyday.
My mates brand new BMW 320d is very nice inside, it's similar to the CX-5, but it does feel more solid, the build quailty a bit better, and the best thing is there is not one squeak or rattle, the seats are sit in seats, like half buckets, not for everyone but much better than the CX5 sit on seats as I find them.
If you decide to go for another CX5 diesel, please test drive it for a good 30 mins, make sure you don't have the high pitched injector noise reported on the latest diesels. There is a fix by way of a injector calibration, but that's just hassle you don't need on a new car. My new CX5 has the noise, but I don't drive it much, my wife doesn't mind it. Also, if you test a model with MRCC, radar cruise control, try it out to see if it is for you. I am on the fence with it, problem is, I can't disable the MRCC part and leave the cruise on (well, I haven't worked it out yet), the chaps in the USA can do it, but their buttons and configured in a different way.
The LED headlights a VERY cool, put them on high beam and don't touch them again, they do everything for you, even light up your side with high beam when a car comes but dips the offside so as not to blind the driver. My gearbox is much slicker than the previous model, feather touch for all gears now. My previous was a bit clunky into reverse and 1st to 2nd. Cabin is quieter and overall feels a nice step up.