Previously, I wrote about purple cubes, but today I will write about Yellow cube on how I feel about this cube and my experiences.
Here is what I think, many of the maplers asked how many yellow cubes they need to up from epic to unique. Here is my answer. You need approx 40-70 yellow cubes with a bit of luck. HOWEVER, as cubing is very random at all times, you may not get a tier up even you used 100+ yellow cubes sometimes.
But, most of the times, I tried 40-70 yellow cubes it gotten a rank up from epic to unique. This is the reason why unique potential scrollis on sale in FM for 9.8b now. There is a reason for this, because you can likely to get a equip from epic to unique within 10b mesos which is equivalent to 100 yellow cubes.
My experience on yellow cubes is quite ok, this cube is recommended for everyone to use from EPIC to unique.
Before you use ANY cash cubes, make sure you only use cash cubes on unique to legendary, use SMC (super miracle cubes) in the cash shop. Epic to unique ALWAYS use yellow cubes in the FM, as I found out that this is the so call free way to do it. It is not worth to spend on cash cubes on epic to unique, tried and tested myself....
So, you use EPS (epic potential scroll) to epic rank, then use yellow cube to unique, then wait for DMT (double miracle time) and use SMC to legendary. This is the best of the best way to cube your equips to legendary. No purple cubes (this cube sucks, the rate of the tier up is maybe less than 2%... sometimes you need to spam more than 200 purple cubes without any tier up.