When comparing ScanSat vs Hot Rockets, the Slant community recommends Hot Rockets for most people. In the question“What are the best Kerbal Space Program mods?” Hot Rockets is ranked 5th while ScanSat is ranked 6th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Create maps
You can create detailed maps of every planet.
Pro Helps with landing the spacecraft
You can use ScanSat to determine the slope of the surface you're landing on and avoid hills and other obstacles.
Pro Much better than the stock scanning system.
The stock resource scanning feature finishes instantly, while ScanSat functions over a long period of time and the orbits you're in, like scanning satellites do IRL.
Pro Science boost
Provides a little extra science to help you in your career and science mode games- but you'll have to work for it!
Pro Very low memory cost
Pro Improves engine effects
Cons
Con Some users experience performance losses
This is only true when the window is open, it shouldn't affect the rest of the game.
Con Unsupported by most mods
This is a very old mod, and as such the modding community has moved on to configurations for different systems. I don't even think the mod is up to date with the most recent stock parts.
Con Better alternatives as of 2021
RealPlume and Waterfall have better performance, look better, and supported by most other mods.