I've been using a rain skirt in the past. I don't like rain pants for being awkward to put on/off, heavy on your back (for an item that usually sees lots of pack time) and sweaty when in use and I haven't used them for years. I've only missed them when it was cold, like close to freezing but it depends also on wind, exposure, etc.
A rain skirt works very well for all those issues with the pants but not so when it's cold/exposed. I usually carry convertible (hiking) pants, wear the skirt over the shorts and let my lower legs get wet. If it's cold, I just wear the full length hiking pants. I try to get pants with a wicking inner that feel not too uncomfortable when wet and of course dry quick. This works quite well. Actually, I find the problem with rain is not as much the falling rain itself but the wet vegetation: if you rub against it (and depending on the type of vegetation and its density), you get as soaked as if dumping in a river. Rain pants could be useful for this too and I might take them if I expect lots of wet vegetation.
For general use in the summer and unless I'm going to a particularly cold/exposed place, I use the skirt. Or unless I'm using a poncho, when a skirt would be redundant.
The chaps could be a good supplement to the skirt (or maybe knee high gaiters) but I've never used them. One of the things I like about the skirt is how quick and simple it is to put on / take off and chaps mean more complexity. The wet hiking pants option is usually good enough for me, the wet pant still protects from wind chill.