I purchased the Pro-Aim via DM's offer.

I find them to be an excellent tool. Helps not only w/ alignment or fixing poor alignment, but also works to keep the head steady during the stroke and also works one the path the putter travels during the stroke. Those are 3 fundamentals that are addressed with on device.

Just need to stay committed to working w/ them.

What kind of offer was it from DM?

It was an offer he had on BSG when they first came out. At the time it was a bit of a discount, but now I think you can get them cheaper than that original deal at any of the online dealers, or maybe even a well-stocked pro-shop.