With minimal practice, the uni-uni, blood-knot, and Alberto all take about the same time/difficulty.
Alberto will win a head to head every time against the other two, test it yourself at home. They all have their own critical step to which if not done correctly, may weaken or fail, so improper tying should not factor into the evaluatiion of the knot.
A good leader knot should never come undone or break unless you cut the line with scissors, if it breaks even when you pull straight back trying to break your line, it makes leader use way less practical. With the Alberto, your leader will break near or at your lure if you intentionally break on a snag or whatever, never at the knot if tied properly.
Now the aforementioned critical step to all of the knots is important, and for the Alberto, that is making sure your tag enters back through the loop the same way it entered. The major mix up here is that when making wraps its not uncommon for the loop to move or flip over while you are focusing on the wraps, which disorients the "correct" way for it to pass through the loop. There is an easy way to check if you passed through correctly before cinching but I will have to make a video to show/describe it properly, which I can probably do this weekend.
With all that being said, the uni-uni is completely fine and works for many and did for me for some time, but the Alberto is just as easy, and stronger.
Stay tuned, I'll make a video on the Alberto hopefully this weekend.