Thanks for info. I used for it for a long time, but I changed when the blockchain passed over 50 Go.
I'm now with Electrum, which has a feature to tell when the confirmation time will be, but only after a transaction is signed. It says 25 blocks for my last transaction. Not very useful...
Using core with a pruned blockchain it can be as small as 550MB. There is no need to have the whole 120GB to still derive the benefits of using the core client.