I have used just about every brand of strap blocks as I don't like metal strap locks after my Precision hit the deck after a mishap with a schaller straplock in about 1982. When the only ones readily available were free with a bottle of grolsch, I accumulated several and have used the cheap ones from ebay/amazon as well as Fender, Ernie Ball, and Harley Benton.
I keep the strap attached to each bass/guitar so they don't get put on and off repeatedly, and as I like to colour match (or at least co-ordinate) the strap to each bass I tend to match or co-ordinate the colour of the strap block as well.
I did have a few no-name blue ebay ones which were more like a solid plastic than silicone and had no stretch at all, but apart from those, all of the others have performed well and I've never had one crack, split or become brittle.