Well, I've worked in the past with Heller kits.
One thing to say : it's not very good.
About eight years ago, I builded a 1/72 scale E-3 Awacs from Heller, and the wing was so warped that I had to heat it with a thermic paint stripper in order to have it straight.
Use a lot of glue, and add bits of plastic to add strenght to their kits. I'm currently building a 1/8 (yes 1/8) scale Traction avant from Heller, and with a huge amount of glue it's ok.
But their kits are interesting, as they are the only brand to produce kits of some aircrafts.
Hope this helps.
Thomas.