definitely worth the effort. I bought a pack of seed in Wilko's for £1 last year. they turned out to be very strong and productive plants (we still have 2 producing) I found them easier to grow than sprouts as they grow open and stay open to a size you want to pick them, we left them go a bit bigger than you see in the shops, the whole stem is covered with them. as with all brassicas you have net them but otherwise no trouble. very productive and delicious.