I've had the same Icon since launch day. I downloaded 8.1 developer preview as soon as it was available. I was having the typical problems people were reporting, faster battery drainage, getting hot while doing anything, start button lag and start screen booting lag, you name it I had it, but the features of 8.1 outweighed the bugs I was experiencing. Then I downloaded the update and everything became much worse. My battery drained 50% in 30 min and my phone was so hot I could barely touch it, and this while it sat idle on my desk at work (with all the things they recommend to turn off turned off). So, I decided last night to bite the bullet and revert back to 8.0 to get the Verizon firmware update (which was installed during the recovery process, thanks nokia), then re-install the 8.1 developer preview. Today I'm having a perfect 8.1 experience. Much improved battery life, my phone hasn't gotten hot once, and once I removed Cortana from my home screen Zero start screen loading lag, the start button does take about 1/2 a second to wake up the phone, but I only have to press it once now.
Interesting side note, I have a white Icon, my mom has a black one and didn't experience any problems....
Anyhoo, that's what worked for me. I'm absolutely loving my Icon.