Good god, this book was a lot of fun. For some reason, it took me an unusually long time to read - just over four weeks. It was odd, because I was very much enjoying it, and it's a very easy read - not too dense or confusing. However, I finally finished it tonight.
I just really enjoy Dumas' sense of adventure. He's really good at creating these elaborate sets of events where you often have a good idea what the conclusion is going to be but you have very little idea of how he's going to get you there. Obviously this is slightly less present here than in the Count of Monte Cristo, that book being more than twice as long and much more strongly focused on the intricate plans of the Count, but there's a fair amount of plotting and treachery here as well. It's definitely a less heavy book (metaphorically as well as literally) than CoMC as well, with much of the start of the book dedicated to the Musketeers (and D'Artagnan) romping around Paris being excellent. However, I did end up emotionally involved and I was even pretty sad when Constance - who I generally found a bit limp - bit the dust. The book is pretty well characterised, and all the Musketeers are really well fleshed out - I had a real sense of who they were as people. Dumas' treatment of his female characters can be a little lacking, and as I said above, Constance fell a bit flat for me; Lady de Winter was a bit of a cartoon villain, though I did appreciate her machinations.
Dumas, as with many of the writers of the time, does have a tendency to digress a little. But I much prefer his method of doing so to, say, Victor Hugo's. Dumas tends to create little side adventures for people to go on that have nothing to do with the plot, whereas Hugo has a tendency to give you a thirty-page history lesson when he could be telling you what happens to the characters in the book he seems to have forgotten he's writing, which I find much more grating.
Half a star off only because I felt there could have been a little more roundedness in the characterisation and I wanted to see a bit more of the queen. However, if you're looking for a thoroughly enjoyable classic read that's not too densely written and witha compelling plot, you really don't need to look any further.