I have used both!
When Wrigley was a puppy we used a regular baby playpen and it contained her just fine!
We had a mesh netting on the top that went down over and secured under the legs.
Well when we rescued Camden a few months ago, she's 2 1/2. She was able to either climb or jump onto the railing and scaled down between the playpen and mesh netting and chewed a hole in the netting to get out!
We now use a crate for her and it works great!