First is you don't own any shares. Not a deal breaker but you have to wait a long time to get back your original share value before turning over a ROI.
Second they have a large sponsor if they decide to pull out then the value will drop. Sor far they have around 140 owned sp and 2500 delegated sp.@steemitbuilder looks ok however i can see a few issues.
Full disclosure this account is also @andrewharland. I do have a vested interest in minnowbuilder. However this my truthful opinion. I own a lot of sbi and think that was/is a great program but the cracks could show if they can't keep up with the purchase of delegated sp.