They have good amount of Japanese maples, hornbeam, and some decent trident trunks. If you can time it to take one of Walter or Jim's workshops; I found a very pleasant atmosphere. I went to the Woodstock workshop and found a nice hornbeam. Here is a picture of the trident and K. Hornbeam I picked up. .
Their best stock, hands down, is evergreens and conifers. I was just there last weekend after attending the MABS show. They have deciduous trees as mentioned but not as many. If you are looking for maples/specific varieties I would suggest calling and asking.