I'm an enthusiast of mining - I've always loved the idea that one can help the Blockchain system by working towards a common goal - plus it's very fun to build a rig and SUPER rewarding to know you're doing your part!
So for me, IOTA has a huge downside which is no mining, since there are no blocks to mine.
The transaction fees I somewhat agree with - you see, I reckon we need to help out a bit when mining and interacting with the system through fees - it keeps the game interesting for everyone in the community - although I would like to pay fewer fees every now and then - I'm looking at you wallet and mining pool masters.