Three main noticeable differences: coloration, material, and design changes.
Coloration: With Starburst, there is a slight metallic look to the red of the chest area. This is really nice when you place him alongside Skywarp and Thundercracker, it gives him a premium look. The TRU version was flat red. Starburst has flat blue instead of metallic, and both TRU and Starburst have a bad case of the swirly gray plastic. Hopefully bb7's starscream, which is supposed to be painted white, will finally give collectors a premium starscream look from head to toe.
Overall, paint details on kbb are fairly good. There is slight softness to the wing lines, but it's not bad
Material: Kbb uses a softer, more forgiving plastic than bb7 or TRU. I don't pretend to know plastic compositions, but this just doesn't feel as "tough" as other Seekers. Kbb does, however, add diecast to the leg sliders, which adds weight and slightly counters the top-heavy nature of seekers,
Design changes: There are a few obvious design changes on Kbb Starburst. Most noticeably, the hip/crotch area has vents and panels instead of being a solid piece as on the TRU starscream. Secondly, there is a mild hip swivel. Fans have long begged for this. The final major change is an extra port on the wings to add accessories.
I do like the metallic flake in the red plastic, as well as the attention to assembly on the kbb. Sprue marks are a minimum, and the ratchets in the limbs hold poses well.
- Design has a good mix of G1 toon and toy.
- Tons of detail. Airbreaks in jet mode and molded afterburner engines.
- Leg articulation is better than official figure. Hips have been modified for greater mobility.
- .Head and chest sit too high above shoulders.