We have both types of toys for Ds who is 11months. I like the plastic because as said before they can be cleaned & you can buy used a lot cheaper than new. We comb garage sales & thrift stores for them. A lot of plastic toys do need batteries & make noises (which can be quite annoying) but we opt to leave the batteries out. I like wood also, plain blocks right now. For me & ds right now it seems that plain household items- whether wood or plastic- fascinate ds the most, spoons, containers, cans, bowls, towels.
I do think the "plain" toys whether wood or plastic foster imaginative play more.