Most common I've seen is the provider register domains as their own, and "allow you to use them", when obviously thats not what you intended when you paid them. Transfer out fees are quite common, despite being a practice that violates ICANN policy. Google a few "hosting nightmare stories" and you'll see a lot of interesting **** being pulled, despite being against TOS, but I'd suggest relying on ICANN is more trouble than it's worth for most folks.
Here is an example of not owning your own domain name trick:-
http://www.javascriptkit.com/howto/hostnight.shtml
Any company selling domains is bound by the terms of the registry, but if an ICANN member gets in trouble it can be a lot more hassle than a company who is a reseller, as there's nobody to turn to.
FWIW many companies use the same few suppliers for many of their TLDs, eg Fasthosts, 123-reg and many hundreds of other companies use Tucows and/or Enom for some gTLD registrations.
Nominet sell .uk domains at fixed prices; ICANN sell domains at fixed prices, etc. There is a small margin added to very small resellers (eg a company with only a low-level Enom account for example) but above a certain level it's fairly equal. Bigger companies have bigger overheads so can be more expensive just as they can be cheaper.
For example, Godaddy and Namecheap are cheap, but Fasthosts charge £9.49 for a .com registration and £10.49 for the renewal. If you can find the £10.49 renewal price listed on their
domains page, you're doing better than me.
123-reg are more expensive, at £10.99/year, also do hosting, and are owned by one of Europe's largest hosting companies. Some companies will have better management tools than others of course.
This is true, which is part of the point I was trying to make. Domainname registry prices are fairly static, so you can basically pick anyone who isn't trying to rip you off, because they're just a glorified intermediary anyway. You seem to be emphasising on the fact I said they could be cheaper, when I was attempting to convay the more established providers are less likely to be considerably more expensive, which may not reflect the costs of their managed hosting.
As must a domain registrar!
I'm oversimplifying, but whilst both require effort to get right, once you write your domain system, and get your billing system right, I've seen hosts tick along for years without much maintenance on their domain registry system. If you grow to the levels of the big domain pushers they'll likely have a team dedicated to this, but in the smaller hosts, it's just one of those things that get ignored until it breaks.
Most "good" web hosting starts off as a pretty primitive undersubscribed with quick support turn arounds. As these companies grow, they have a lot of teething issues, and this is when their customers start jumping ship to the next undersub'd host, and they repeat this ad nauseum. I have nothing against host hoppers, but it doesn't take long to find people who have massive problems moving host, when in reality the only thing that you stop you are up-to-date backups, and a the ability to change your a records.
My statement doesn't reflect the opinions of the recommendations given on this forum, I offer no opinion on any of the providers mentioned just general opinions.
Ever called 123-reg at 10p/min? (Once you find their number)
No, but then I wouldn't need to.
Why would anyone "fiddle" with your DNS?
Sometimes for legitimate reasons such as migrating customers between servers, other times for not so legitimate reasons. Doesn't take long to find instances of this on google, either. Heres an example.
http://jkt.im/2010/10/13/when-businesses-go-bad-xcalibre-sells-out-to-webfusion/
Additionally, at least with .uk domains, if you have an issue with your registrar, you can go directly to Nominet for help.
I'll be honest with you, I don't work on this day-to-day, but last I checked I'm sure going to the source for a transfer would cost around £100; though it now seems to cost about £10. Either way, go back to my original 'pulling ****' example, and it's fun when you find out the whois specifies someone from the company you bought with, as opposed to you.
I think the most important point is to find a company (or two) you can easily contact and work with, and go from there.
You're completely right, of course. I was just weighing in with the argument, that some companies can be good at one, but not the other, and when we're talking about cheap shared hosting, I generally don't consider it good practice to host my domains with such companies, even though I can understand trying them as a web host.