Nikki, I'm loving all the BSP dies! Everything is so big and useful. I love my other dies, but they make such small cards, bags, & boxes -- which are cute for little things and I do love them, but often not quite big enough.
The BSP envie dies are great. You can put an M&S shape die in if you want a window or leave it out if you don't. There are M&S shape dies in the Clearance/Outlet section of sizzix.com. I've also put in Sizzlet & QK dies and they work, so in reality you could have just about any shape window you want. Just shim whatever non-M&S die you put in the little depression/pool space of the envie/platform die and test with scrap paper. (Sizzix Originals are too thick.)
If you don't want an M&S die for your envie, Ellison has non-M&S envie dies. I bought a couple during their big Spring Clearance for $15. If you sign up for their newsletter, you get notified of their sales.
Ellison Card & Envie dies
I was able to get the extended accessories (the long tray, adapter pad, and cutting pads like those sold with the purple/Westminster BSP) at a good price from
It's Cheaper Than Therapy. They weren't listed on the site at the time, but I sent Maria an email and she fixed me up with the longer tray & such I need for the new line of dies (the 25" long dies for the BSP and the BS/BK). I also bought the dies from her and the extended accessories for my BK. When you're ready to purchase, keep her site in mind. When I bought my BSP, she had the best deal going. Not sure if that's the case now, but her BSP dies are a good price and she has free shipping over $100. She ships super-quick and I've never had a problem with an order. (Ritz and ohmycrafts BSP dies are $2-3 less, but they don't ship as fast and I've had issues with both those sites off & on. I did just place an order with OMC yesterday because they had a Cricut cart at a good price and I had a coupon code, so I've got my fingers crossed.)
Okay, um, I got a little Sizzix excited, but I know you know how that goes! :-D