Okay, let's see (and bear in mind this is only my opinion)
Personally I think the 'Rat beats the rest for dovetailing. Not that it's the easiest, 'cos it isn't. But in my opinion it's the closest you can get to hand cut dovetails with a router, and you can use any make of cutter you like rather than being stuck with whichever one fits your jig. If you want to have an easy life though, you're probably better off with more of a "point and shoot" jig, although the 'Rat's little brother gives something like that option if you wanted. Personally I wouldn't want to give up the flexibility, but horses for courses. I like cutting tenons on the 'Rat, but I know others find it difficult. It certainly gives a better result than anything else I've tried, including a shoulder plane, so it's worth getting the knack of it. One reviewer actually reckoned it'd be worth getting just for the tenoning ability.
Getting to understand the Woodrat is not easy, and taking one of Mike Humphries' courses is often recommended. If you have the right sort of mind for it, it's less of a learning curve; I don't, so I've struggled a bit at times. However despite this, and even thinking of selling it at one time, when it comes to it I'd miss its capabilities too much to lose it. As an example, I've made a couple of shaker pieces that needed sliding dovetails to join three legs to a central turned post. I'm sure you know the sort of thing. On the 'Rat I was able not only to cut the tenon half of the joint on the curved legs without needing to make any kind of jig or special holding method, but with a simple workshop-made "sugar tong vice", as suggested in the manual, I was able to rout the mortise half in the turned leg too. Without the 'Rat I'd have to have made a bulky box to use with the lathe, while somehow getting the headstock to stay still etc, and then find somewhere to store it 'til the next time. Incidentally, the 'Rat is excellent at sliding dovetails and turns them into the easy option, so I use them a lot now.
To be honest I haven't done a lot of freehand work with it, but it's certainly capable of profiling the edges of round table tops. You might want to get hold of the CD-Rom which shows an example IIRC. One of the things I like is that you can use the north/south and east/west movement the Woodrat provides to rout housings, grooves and recesses all without having to clamp straight edges in just the right spot and all that palaver.
I hope that helps a bit. Like I said, it's not a simple case of "buy it". Only you can really know if it'll be the right thing for you. It might help to have a look at the manual and various downloads available on Woodrat's site. That'll soon give you an idea of whether you think you could get your head round it or not (kill or cure possibly!) If you can then for my money the 'Rat beats the table/jig combo every time. Which explains why I bought one. :lol:
Cheers, Alf