There is certainly not a significant difference from 600mg to 800mg of Boldenone, and I can say that as i have used it more than once and at various dosages.
Whether there is a difference, i think it is pretty safe to say there is but i would not call it even close to significant.
The results from that drug are bordering on insignificant to begin with, which coupled with the fact that at that dose of AAS, the dose:response curve is already flattening out somewhat for most if not all AAS, so the increase in results is going to be less than the increase between two lower doses (175mg and 375mg for example, which IMO is the difference between decent results and fuck all and would in my opinion be the most significant 200mg leap you could have with that drug.. IMO..)
I am not a massive fan BUT if you get high quality gear and especially if you are a steroid virgin, you will probably really enjoy it.
I do wish i had used it earlier on in my steroid using life, when its results would have been more dramatic..