Maturity is beginning to appear
I bought mine when it was €399, it's nice that the quantity they have sold has enabled them to drop the price by €50. The OS was at version 1.03 and has been regularly updated and is now at 1.08.
When I first got it, there where known issues with MMS and 4G, these have now been dealt with.
I have had no issues with call quality, it reminds me of my old nokia 3310 in that it still operates well with only one bar of signal.
The camera is not the best on a phone but is more than adequate, with the option of standard form or 16:9 photographs.
Sailfish is still under development and keeps improving. It is already very fluid and smooth in operation. The Dalvik virtual machine is really very good and is capable of running the google play store if you want to do that. The Yandex store that is used if you install the DVM ( I don't know if that is automatic now ) is a little deficient in terms of volume of apps, as is the native warehouse but both are slowly improving.
I do recommend putting it in developer mode, it will download a bash terminal which then gives you access to the system as a whole and root as well. It also opens up a lot of applications that are command line from the warehouse.
This is not a smart phone, this is a mobile GNU/Linux system with a very good communication system that happens to do good voice as well.
As long as they don't stuff it full of provider carp it should do ok.
Good luck Jolla, it's a good system, it deserves to succeed.