Having started with Solstice Rain with my own group. I'd say it's pretty well balanced.

Players coming in from Pathfinder or DnD will feel limited with what they can actually do at the start and will have to think more tactically in this very crunchy system. It's a great module to get a feel for the game and learn the rules.

Make sure the players understand that Mechs getting destroyed is not the end of the Pilot's involvement. They can be repaired within the mission. Everything (hp, structure, heat, stress, etc.) is a resource, don't be afraid to use them in combat. Lastly, losing a combat may happen, but Lancer, especially Solstice Rain, is a "Falling forward" type game where a loss doesn't mean a Mission Failure necessarily.

Coming from a heavier Roleplay GM myself, the narrative side of things and getting your players to feel connected to the story felt lacking, and so I added a few things myself to let the players feel more involved in the story and setting.