I use it everyday, just to check email messages, make sure the house hadn't burned down etc and didn't notice the charges, so it can't have amounted to more than a few $. It's slow for browsing the web though, it was still dial up when we sailed NOS.
I had the opportunity to use the internet on board the Radiance and it worked fine. Like Queen of Diamonds I like to check briefly my email to be sure family and friends are o.k I noticed it was working very well for everyone else who tried too.
No it wasn't as fast as my home internet but it wasn't agonizingly slow either. I did make a mistake at first...I tried to log on using my local home server which BTW is lousy even on my home turf...finally after noting everyone else's success I got smart and used one of the featured servers on the screen. Perfection....
Now for just web browsing it might not be that great.
My husband and I have iPhones and kept them in air plane mode where we could listen to music etc. but we couldn't check our email or send text messages. The cost would have been outrageous because we would be charged by the minute as the phone attempted to down load all email, text messages and updated apps, and iPhones WILL try to update and download automatically when you first turn them on. And at sea this would have been super slow and $$$$$$$
Yes the internet is slow. It is a little faster than dialup, but not much.
That being said, I always bring my laptop or netbook so I can get on-line or empty the memory card if necessary.
Just about every port has free wifi.
Every Margaritaville or Hard Rock Cafe I have been to has it plus just about every other bar. At some of the smaller bars they offer it, but you have to ask for the passcode. As long as you buy a drink they will happily provide it.
I also have had very good luck in picking up free wifi from the ship. Try your balcony first then if that doesnt' work try each corner of the ship.