I have the Saleae Logic that SFE sells. I can give a review, but I don’t think there’s much more that I can say than you can find out yourself from the product page and the demo software.
It has been very helpful in debugging interface connections. SPI, I2C, serial, RF. It was well worth the money.
With digital electronics I don’t have a whole lot of use for an o-scope. There’s been time when it would have been nice to have, but not worth the price for what I do.