Congrats on getting your new baby soon, he is a cutie!!
Well I only have the metal ones. I don't think they are any harder to clean but I do like the look of the plastic ones much better. I wonder which one would be sturdier though and which one has more flexibility.
I don't know if it is an issue with the plastic ones but I think the metal ones are sometimes too easy to move around.
Some yorkies are known for climbing or jumping which is why a top is good to have. My girl Destiny is only 5lbs but can climb out any size one very easily. Most expens have it where you can purchase a top for it.
Walmart has some plastic ones.
Walmart.com: IRIS 8 Panel Indoor / Outdoor Heavy-Duty Pen, White: Dogs
They also have soft sided pens now that have a top and a bottom. These look great but I'm not sure if they would move around too much because of being too light or if the puppy would be able to chew through it? A lot of members have boughten these and have been very happy with them though.
NEW 45" PET PUPPY DOG PLAYPEN EXERCISE PEN KENNEL GREEN - eBay (item 370487898113 end time Mar-04-11 11:00:12 PST)