I went and cleared as many of the second tier challenges in story mode as I could before they removed the mana crystal rewards, and now I have 237 crystals. I have 206 cards, but there are a handful that I still want. However, I know that if I spend my crystals on a fat pack, I’m just going to get duplicates. -_-;
Sorry can’t help you with that. With that amount of cards I would spend those crystals on fat packs. I think you will still have good chances to get some new shiny cards.
Only reasons to not do it
- keeping those crystals for future PWs
- if you get to place 1 to 6 every quick battle
- waiting for new cards been added to the game
- waiting until you have 600 for a big box
Personally I wouldn’t do the last thing until we figured out the chances of big boxes though
That’s exactly why I haven’t purchased a 2nd big box yet. Plus if new Planeswalkers or cards come out, the crystals will be more valuable.
Okay, I broke down and got a fat pack. I got a Despoiler of Souls and a Woodland Behemoth, so it was a good pack! Then I opened my free monthly fat pack and didn’t get anything worthwhile… so 
stabstabstabstabstabstabstab
How I hate this creature. Good draw.
I so want both of those. Good pull.