We have:
Dragon Door: two 12kg, two 16kg, two 24kg
Mbody: 4kg, 8kg
and a teeny Gold's Gym 5 pounder (belongs to DD
)
We also had (and sold) a 70 lb. Ader and 70 lb. Dragon Door. DH says the Ader had a really nice, slick handle...but it didn't feel symmetrical (crooked handle). He really liked the 70 lb. DD.
But we'll probably try/buy Lifeline next time we get a chance. They seem comparable to DD and they're USA-made. Prices are better than DD, too.
Right now, my most used are 8kg and 12kg. DH (obviously) uses heavier.