Just plain Hulu on a computer is great for watching stuff so long as you don't mind ads, since they probably have the best and most stable video player on the web and it plays at good quality. I've never tried out Hulu Plus, but it doesn't seem to be necessary to watch any anime over a regular computer, but seems to be the only option available for mobile devices and game consoles.
So Hulu seems to be a good option for desktops and laptops, may not be great for anything else that can only get Plus (especially if, as Joshua has said, there are still ads). Also, on the few occasions where Hulu was missing a few episodes of Dragonball (as in there were weird jumps between episode numbers available) I've been able to find them on Funimation's website, which seems to use Hulu's video player and has, I think, the same sort selection of Funimation shows available (which leads me to assume there was some sort of two-way leasing agreement involved). I think the website itself might have been a bit slower (but not the videos themselves), but I think there were less ads shown, and it doesn't automatically play the next video in the series at the end of each video unless you uncheck a box that you can seemingly only access by having an account like Hulu does. Probably the only reason I like Hulu better is that I watch a bunch of non-anime shows too, and I already have an account so that I can subscribe to them and it sort of keeps track of what episode I was on while I'm logged in, which is good for long anime series.