I'm so happy to read ratings of Xilinx here. I'm a novice to the world of FPGA, and I've spent so much time fighting the tools.
My very favorite issue is with their IDE. The version I'm using has a broken search and replace... if the two strings have different lengths, the editor loses its place after the first replacement -- they compute the location of matches and then just smash the replacement strings in... failing to maintain an offset as character offsets change. Makes me scream.
I'm using Vivado after having previously attempted Quartus and I can't actually say it's any worse. I was able to eventually find my way around it and in some ways it was more intuitive than Quartus.
I see the pile of ideas they're trying to glue together. But it really just does get in the way more than anything else.
Now my process is: Verilator + CMake + CLion + SystemVerilog plugin for CLion (excellent but $$$); then when it runs well in verilator I bring it over to Vivado, fix any warnings it gripes about and try it on hardware.
There are two things that amaze me:
1. That the dumpster fire is actually capable at all to synthesize hardware without exploding
2. That their head of software still has a job.