Far as accuracy, they are the same. The blue model is one of the best lower priced units we have found, that said it's still a little flimsy. It's not going to just fall apart, but rough handling could wear it out in the future.
Sybon is just heavier, stronger material, little better quality. So it's just build better.
If you take these out of the case, use them and put back, you probably would never wear one out. To give you an example on the blue model though. We tried at the shop and means several employees handling it, toss it in a cabinet and back and after a few months we had the eye piece coming loose.
thanks