I actually got into Pd because I wanted to make generative music a while back. I only have limited experience with Reaktor, but I found it less suitable for generative or algorithmic music. Reaktor is great for synthesis, but it's lacking on the control side compared to Pd, so it's not so great for composing if you want to use it on its own.
These days I don't have the time for making any music beyond simple studies or just playing around, but I do use Pd for my Master's research. Mainly in DSP and synthesis. From someone who came from a music background and is used to dealing with guitar setups, mixers, and things like that, I find the graphical approach very intuitive. I can think of the overall patch in terms of the signal flow. Most people studying DSP come from more of an engineering background and prefer to think in equations, and I've found they hate Pd and Max. But the musicians I've met are much more comfortable with the dataflow approach. So it's a nice bridge between those two worlds.
I used Max/MSP for a while, and still do when I have to, but I find I patch much slower in Max. All those nifty gui goodies that draw people to it are in fact incredible time wasters. Even though I know this, the fact that I can make it look prettier makes me do it, and I don't get as much done. Beyond the gui, the differences are pretty subtle. Some things are a little easier in Max, some are a little easier in Pd. I personally find the frustrating things about Max are more frustrating than the ones in Pd. Also, Pd has been more stable from my experience.
As for modern DAWs, if there's something you want to do but can't in a DAW, then you just can't do it. You may have to build it from scratch in Pd, and it may take some serious studying, but you can probably find a way to do it. I almost never use DAWs anymore because they are full of things I don't need to do and don't do things I want them to. You can get them to talk to each other to an extent using things like Jack, so if you need them both, you can potentially find a workaround. Max4Live is probably the only thing that has really integrated the two worlds as well as it has, and in my opinion is the only significant reason to go with Max...if you have a LOT of money to burn.
The only other thing I've used extensively is Csound. Csound is pretty awesome in its own right, and it has a boatload of opcodes. The sound generators themselves are pretty great and diverse, which is the reason, I think, everyone says Csound sounds so good. It is, however, pretty old school. Its a direct descendant of Max Mathews' Music language, and there are still plenty of similarities. There are two main things that eventually led me to use it less: 1) Being text-based, patch cords are replaced with variables, which kills the signal flow visualization for me. 2) It doesn't have a real-time interpreter, which can make programming really slow. Having the patch running while you work on it feels like the programming equivalent of jamming to me, and it really allows for a more fluid, stream-of-consciousness approach. You can run Csound inside Pd using the [csoundapi~] object, though. So if there's a filter or whatever in Csound and you want to use it in Pd, you can. Their community is really nice, also.
I find the Pd community overall to be quite nice, and it's a big reason why I stuck around with it. Actually, I like the two different crowds that are attracted to this forum and the list. This forum seems more newbie-friendly, people are less afraid to ask dumb questions, and there seems to be more patches shared. The list draws some of the really experienced guys, devs, and people just discussing the more esoteric aspects of Pd that fly over newbies' heads. The main reason I spend so much time here is because it helped me when I was new, and I feel I can be more helpful to others here. And I can lurk the list and pass on info that doesn't come up here. 
The Max community seems to suffer from its largeness. Most of them are nice, but there are enough who start flame wars, and it gets really damn annoying. And you don't really get direct access to the devs. I will say that I find the devs for Csound to be more responsive, though. You can report a bug and it will often be fixed that day. (Of course, part of that could also be because Csound has been around forever and the community is pretty small these days.) It seems the Pd devs on the list spend quite a bit of time arguing over what is the right or wrong way to do something instead of just doing it. I mean, having the debate is a good thing, but at times it seems to drag on until nothing happens. Things just get implemented slower than they should, and it's particularly difficult to get features past Miller into Pd-vanilla. This is probably my one major gripe about Pd.
