Thanks for the replies! After reading them I'm thinking the 3.1 ghz will be totally fine for my purposes. Currently I've a MBA mid-2013 and it has difficulties with some tasks, like: converting video from format to another, running a virtual machine, editing photos/video, having a large number of Chrome tabs open (like 20). 4k videos won't play at all. Would that kind of tasks be easier with the 2017 MBP? I'd especially like to have a fluent experience editing photos without any lag. I'm thinking upgrading the RAM to 16 GB... what do you say? Perhaps SSD upgrade isn't worth the money - I think it's not good to keep large amount of media files on your SSD, they should be stored in a RAID1 protected NAS station.
So again, my usage purposes:
- having a large number of Chrome tabs open (up to 20) and other apps like Word, Excel etc. simultaneously open
- converting videos
- running a virtual machine (could be a Windows 10)
- editing photos and videos
- 4k video playing
- large Excel spreadsheets should open without issues