Ive been thinking about trying it out due to the mud & crap that gets on the chain at this time of the year.
It seems like a good idea!
Scottoiler

Used to fit them onto motorbikes. Most of the time they were a waste of money. Owners didn't look after them properly or get them out of alignment when altering their chain tension. Bicycle ones maybe different though.

brilliant things. On a motorbike, controlled by intake vacuum. on a bicycle, less enthused

As above, really good on my motorbike but wouldn't bother on a push bike. Just use a good thick oil if it's really wet.

Brilliant on a road going motorbike.

i got a cheap one for my motorbike and after a bit of faffing it was age but i'd not bother with one on a mountainbike

I concur. On road motorbikes they are ace cos they are automatic. The bike one seems like a waste of time. You have to pump it by hand to make it work and to be honest I doubt that it's going to clean the crap off so that the oil gets where it's it's needed. Better off with a water bottle to wash crud off your chain/cassette/jockey wheels and then some spray lube to get your chain and jockeys freed up again.

Save your cash.

I have one on the motorbike – great.

Had one on a mountain bike as well – also great. It wasn't so much that it kept the chain lubed (which it did), but more that it enabled me to use really thin, Scottoiler lube. This did not bind to mud and dirt like normal lube, and meant cleaning the chain was much easier.

So I cleaned the chain more often.

So the chain stayed clean, fresh and new.

That bike always chainged like a dream.

I don't use the scottoiler anymore, only because I swapped that bike for a singlespeed. (so OK, I guess that makes me strange 😉 )