I have shot a variety of ammo through my Mini-30 with a variety of results.
This is a non-scientific rating of the ammo.
The variables that I will not specify are: stock, shooting position, and magazine. For most of these, I tried more than one of each. I used iron sights, so there's something to consider.
Here's the gun in its two forms:
I used 3 different mags listed in order of reliability with the most reliable first:
Ruger 5rd.
Promag Steel 10rd.
Promag Polymer 30rd.
Here is the ammo:

These are good but expensive.
This was tied for most reliable with the next one.
They were the 2nd most accurate.
This box cost $15 at the range.

These are good.
This was tied for most reliable with the first one.
These two were the only brass cases and also the only ones with zero failures.
These were very accurate, but I would rate them 3rd.
This box cost $11 on the internet.

These had a 5% failure rate.
These were the most accurate and had the strongest kick.
They smelled odd and had a distinctly red muzzle flash.
They soiled my gun much more than the brass cased stuff.
This box cost $5 at a pawn shop.
They are a no-name Russian type with polymer coated steel cases. They have the same quality symbols on the box as the Military Classic and the Brown Bear.

These are terrible.
They had a 15% failure rate.
They were the least accurate.
This box cost $8 at a pawn shop.

These were the worst.
They had a 20% failure rate.
The lacquer coating provided enough friction between rounds to prevent the next round from shearing off the magazine >1/3 the time.
Their accuracy was a close 2nd to worst.
This box cost $8 at a pawn shop.

These were decent.
They had a %10 failure rate.
They were accurate.
This box cost $9 at a pawn shop.