I think the spotting scope is a necessary addition to the FirstScope. Having tried to use it without the smaller scope, I can attest that it's not easy to line up correctly, especially at the higher magnifications. The spotting scope is a bit difficult to set up, but is invaluable.
Pros: Inexpensive, Spotting scope is great aid
Cons: Spotting scope difficult to align
This review was written in the old system and had content requirements that are different than reviews written today.