When I bought bands I was pumped to use the biggest bands and just kill it......... didn't happen. I bought my bands from elite fts.
I bought mini to strong, I use the mini and the monster minis, I use the light bands every now and then, but mainly the mini and monster mini.
The medium and strong bands just look cool hanging off my rack but NEVER get used. I deadlift 415lbs, squat 315lbs, bench 225lbs.
My advice is, if you want to buy the level 3 band, also buy level 2 and 4 so you can feel the difference and see what you like and can handle.
Bands are awesome though, have fun with your purchase.