They are covered for one year but you have to think about normally a week or possibly more turn around time you could be without your device while its being shipped and fixed.
Warranty coverages are about what you expect from any electronics these days.. Hardware failures, (doesn't cover screen cracks/shattered), USB port failure's which are common are covered usually unless its a solder joint that has been broken, causing the problem in which they fault that of the consumer for abuse. TEP is about the same coverages, they do cover a single break/crack up to 1 inch in length. Used to cover screen breakage no matter how bad but that was soon dismissed as many people purposely took advantage of that to get either a full replacement or a new screen due to a small crack(s) of their own doing from being mistreated.
Plus hope that whatever your sending it in for HTC or whatever manufacture doesn't decide they don't want to cover it. I have seen that happen from Samsung and it burned up a 2 weeks of time and the customer wasn't made aware of Sammy's decision not to fix the device until it was sent back with an enclosed explanation.
Ultimately its your choice but I feel its worth the TEP for normally a 2-3 day turn around or sooner on replacements and your made aware immediately if they are going to do it for free under TEP or if its going to cost you the replacement fee.