I intended to buy the Fiesta and was happy with it after my test drive, until I test drove a Sonic. The Sonic was so much better I never really looked back, although I did get back into the Fiesta for a second test drive just to see if I was crazy. Nope, still Sonic. And that was the 1.8. I bought the Turbo, and it's better than the 1.8... and I modded the daylights out of it and it's better still. You won't be able to drive a tuned 1.4 so you'll just have to guess at what that will feel like.
I have had the transmission problems, though. They seem to be rare, but they do seem to be happening, to the extent that they exist, in the 6 speed manual. My first transmission developed a problem popping out of third, and the replacement one has an issue grinding going into second from third and into fifth from fourth, and won't go into reverse at all until I let up a little on the clutch. To my shock, my local dealership says the problems with this second transmission are typical of an "econobox" and refuses to fix it under the warranty. It doesn't make the car undrivable, and I am very busy this time of year, so I won't get a "second opinion" from another dealership until later, but I can say that the problems do exist.
As others have said, though, they appear to be quite rare, and there's a solid warranty which should mean if you draw bad luck you just get a fresh one swapped in.
I love the car and wouldn't trade it for the world... although I do have a 6 speed out of a cruze sitting on my porch that I might swap in this fall.