1. Spammy offers – You cannot simply register a domain without saying “No, thanks” to 100 other offers of hosting, certificates and many other things which you don’t need.
2. Complicated site – Site si full of special offers and ads, but when you want to manage your services you just get lost.
3. Payments policy – It seems impossible to just pay with Paypal the amount in your cart. They want subscriptions and payment agreements so they can take money from you automatically in the future.
4. Slow DNS and whois changes – Whenever you update name servers, DNS records or whois records it may take hours until your changes go live while other registrars do it instantly.
5. Slow website – Their site uses too many images and javascript, sometimes killing your browser and the login process takes long.

This is just my experience, I’ve heard others saying much horror things about them. Conclusion? Don’t go daddy!