As you said +damage + health, but really? No.
Use your Lab only to upgrade units that are really effective considering their effectiveness/training time. Use samples if you have a level 10 Cantina. I have hundreds of gamo samples, rarely I use them.
SWC Windows survivor.
Imperial Prestige / Rebel Prestige on vacation and trying new games.
If you are Rebel join "Solo's_Band" (war squad) or "Ewok_revenge" (training squad)