When comparing Deadly Reentry vs ScanSat, the Slant community recommends ScanSat for most people. In the question“What are the best Kerbal Space Program mods?” ScanSat is ranked 6th while Deadly Reentry is ranked 34th. The most important reason people chose ScanSat is:
You can create detailed maps of every planet.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Add reentry heating
As the craft comes in from outer space and into and through gases in the atmosphere it will get damaged by the heat. Mod includes heat shield for reentry.
Pro Adds g-force overloads
Crew can die from inability to cope with weight produced by acceleration.
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!
Cons
Con Can cause damage at speeds well below reentry heating
Con G-forces and reentry heating are already part of the game
Con Does not support KSP 0.25 Windows x64 release
Con Some users experience performance losses
This is only true when the window is open, it shouldn't affect the rest of the game.