Blue Diamond is definitely nice. But it's not several times better than Master to justify it's several times higher price. But that's up to the individual to decide value.
BD goes on smoother and coats better. I don't believe it has any better gripping properties than Master. However, because it coats the tip easier and better, and seems to last longer on the tip - this *may* reduce miscues or the chance of miscues.
However, if you properly coat a tip with Master - it will be just as good. The thing is, it takes more work to get that same well chalked tip with Master than it does BD. On a shiny tip or a tip that needs to be scuffed, Master can be a real chore to get to stick and get a good coating. BD is much easier. Literally just brushes on in two or three swipes at most and it's good to go. With Master, you got to really work it on there sometimes.
Speaking of shiny tips...BD will save your tip somewhat. Because it goes on well and sticks better than Master, you'll find yourself scuffing your tip less. But this is offset by the higher price of the chalk. Master is cheaper, but you have to keep the tip rough for it to grab well.
I feel the opposite of other players, I feel BD can be messy. It doesn't flake off or shed off like Master - which is good. But BD goes on thick and creates just as much dust. I don't consider this a problem. Either a tip is properly chalked or it's not. If it's properly chalked - there's chalk on the tip. Which means there will be dust and mess. No getting around that. There's no such thing as well chalked tip that is "clean" ...Well chalked tips create dust. Just part of the game.
One thing that I like about BD is that its color perfectly matches tournament blue cloth. I can't see it on the cloth at all. This is good as it doesn't make the table look messy, but the downside is it's harder to see during cleanup. But I vacuum the entire surface regardless of whether there are chalk spots - so this is moot point for me. Master blue doesn't match. It shows everywhere I do a power draw I see a streak of it where the impact was.
I'm not certain which chalk lasts longer. BD seems softer to me. Softer, but more gritty/abrasive. My BD chalk wears out faster than Master. But I cannot claim that. It's probably MY chalking technique and habits. Because I'm used to Master and having to work it on there well, BD is wearing down faster than it should. BD goes on easier, and doesn't need to be used the way one uses Master. Takes less to apply it. If done that way, it probably lasts just as long as Master if not longer. Habits are hard to break. I don't want to have to change my chalking technique or habits. Because I may not always have BD. Master is everywhere. Better to be used to the chalk that's ubiquitous in the pool world.
The reason I say BD is more abrasive is that many times I've scraped the forearm of my cue against a piece of Master chalk that I forgot to move out of the way on the rail or didn't see and it didn't scratch. Did that with BD, and it really scratched up the finish.
As I said at the beginning of this post, BD is better than Master and a higher quality, easier to apply chalk. But, it's not some advantage or that much better to justify it's cost. It's an expensive chalk. I think various pros don't mind the cost because what's the cost of the chalk vs. the money to be won in a tournament or gambling? To them, it's simply just the cost of doing business. If it saves them that one less miscue a year, that's cash. At their level, the winner is often the one who made one less mistake. If I miscue, what do I lose? I might lose some cheap set, a league match, or a local tourney. No big deal. Against some of the people I play (amateurs like myself), a miscue error might not even factor into the win/loss result. For pros, who play to put food on the table - I can understand wanting to minimize risk.
Right now I'm using both. I use BD on my well used, thin and fully compressed tips. Because I don't want to scuff them which wears them faster and have to replace them because they are at that perfect stage. I can keep them a little longer time this way. I use Master on everything else.
I probably won't get any more BD. The advantages I listed in this post just aren't that great (for me). But that's for each player to decide.
I think those that are raving about Blue Diamond are over exaggerating. I think those who say it's no different are oblivious to actual differences. In this case, the truth is somewhere in the middle. I hope my post was informative.