You are going to have a very hard time finding any info on Coast/Northwinds online. They deal with their resellers pretty much exclusively and don't publish a whole lot online. You have to do some guessing or else bite the bullet on going to a dealer. This is my main gripe with Coast. We have a Coast Freedom. Bought it last August. The Northwinds tubs are similar with a few downgrades like controls, control panel, warranty. etc. I would compare the Hotspring Hotspot series more with Northwinds from Coast.
The most important thing is that the tub fits, and you are good with working with your dealer. That goes for any brand of tub. Coast uses pretty typical stuff like Balboa controls, and waterway parts, so I can't imagine Northwinds using much less. Looking at them they have a few less selectable features but if this is your first hot tub, then depending on what you are after, it might be worth trying to wet test it. Also be aware of the warranty difference between Coast and Northwinds as there is a difference.