Threw my personal experience, my Nexus 5 does get a bit warmer than usual when charging wirelessly, but it isn't hot. Wireless charging take 3 hours on my Nexus 5 with this charging plate compared to the 2 hours required using the stock USB charger.
Overall, this is a great product for people who wants to charge their Qi compatible devices wirelessly. I rather put my trust in a bigger company (Nokia) than risking my device on a 3rd party charger. Also this charging plate was only $25 from the AT&T online store. Compare this to the $50 official Nexus wireless charger. This is why I bought this instead of the one made by Google.