We don't have nearly enough miles on ours (only about 6,000), and no sign of transmission difficulties for me to directly relate.
I will say though, that the early Impreza CVT seemed to have more frequent failures due to input bearing failure than the later ones have been having. I do not, in any way, agree with Subaru of America's recommendation to service the CVT once every 100,000 miles. That is not realistic and not the way that maintenance should be performed on a car that is expected to last a long time. On any automatic or CVT transmission, I recommend following these general maintenance guidelines:
20,000: Fluid check
40,000: Sump filter clean and fluid change
60,000: Fluid check
80,000: Sump filter clean and fluid flush
100,000: Fluid check
120,000: Sump filter clean and fluid change
140,000: Fluid check
160,000: R&R Assembly to replace internal filters, sump filter clean, reseal, and fluid flush.
CVTs are not like the old gear driven automatics, and they are still relatively new technology, which means that service intervals, maintenance, and proper care still need time to fully evolve. So far, no one has really nailed the reliable CVT yet, they all have issues. All those things in kind, it is always recommended to exceed the maintenance suggestions to keep it in top shape.
That said, a brand new CVT from Subaru will run $7k including labor costs, but a replacement CVT can be found for much cheaper and installed by a reputable service shop with a warranty for a reasonable cost. I would highly recommend performing the 160,000 mile service that I noted above on any secondhand CVT that you may find. Ask the shop you choose about their experience with CVTs and Subarus, and be very picky about the shop you choose. Asking the right questions can ensure a great shop experience for both business and customer.
I hope it goes your way and you can get your Subie back on the road soon. Subaru does most things very, very well, but the CVT may be a bit of a misstep on the Impreza.