What's best to retreat outdoor decks these days?

Cheaper acrylic? stains/sealers seem to last one or two seasons ten start flaking/peeling off, and the whole procedure then has to be done again :-(

I'm after a dark finish to obliterate the few well adhered bits of old stuff - if that makes a difference

Any good/bad experiences and product +s (or -s) welcome

TIA

Jim K