I’ve done it 3 times now
First was your bog standard 0% finance for a year deal, no discounts, nuffink. Paid off after a year.
Second was a sale bike, but The shop added the cost of the finance to the price advertised (8% I think, total price was still waaay less than RRP) was for a year but paid it off in 6 months for no penalty.
3rd I got a 0% credit card for 20 months, set up a direct debt to clear it at 19 months, ended up paying back after a year.
As long as you can very comfortably afford the repayments (or are disciplined with a CC) then I think it’s a pretty good way to buy stuff. It did wonders for my credit score too.
Not sure I’d want to start getting into longer term agreements though, but I’m fickle and like to change/accumulate bikes so wouldn’t want to be saddled with something I could only afford on a 36+ month agreement.