An advancer makes the bike more tractable at low revs and easier to start which is definitely useful, the trade-off is a slightly lower peak power figure which in the real world you won't notice. It is easy to fit, the only issue is the retaining bolt which can be pretty tight, I put the bike in gear and blocks under the rear wheel to stop it turning, I'd invest in a replacement gasket before starting the job.My bike has the full monty and a decent end can, I wouldn't go back to the stock timing.