Strengths: very well made,cleans chain well,very good value for money...what more can i say.
Weaknesses: none
Overall: I've tried other more exspensive chain cleaners in the past and at some point they have all broken. This is very well made and for £12.99 you won't go wrong,excellent value for money
Strengths: Not to expensive, does its job well, seems sturdy, makes chain gleam and therefore more attractive to lady bikes (maybe)
Weaknesses: None so far
Overall: I use mine after every ride (ahem, well almost) as I live on the coast and get paranoid about salt corrosion and sand in my drivetrain. You should see the amount of crap it tales off the chain. Its a great, top value piece of kit, Get one before your chain falls to bits!
Strengths: Gets chain very clean Cheaper than the Park version
Weaknesses: Always falls off the chain Citrus cleaner you get with it it crap
Overall: It gets the chain sparkling clean when you use it with white spirit or other organic solvents so cant fault it. It does however have a tendency to fall off the chain spilling oily mess everywhere is a pain.
Strengths: Every Bike should come with one fill the thing with cleaner. Attach to the rear mech clip shut and off you go. Five minutes later clean chain.
Weaknesses: Bit fiddly till you get the hang of it.
Overall: Great bit of kit that takes just some of the pain of cleaning out.
Strengths: Clean horrifically dirty chains without having to take them off so saves on snap off Shimano pins. Cheaper than Park as said below. Really does save a fair amount of time
Weaknesses: Citrus stuff that comes with is rubbish, Finish Line EcoTech instead in use. Takes a while to get the knack of using it without making it fall apart or the chain fall out of it. Might well conspire to break one day.
Overall: Has lasted a good long time. A bit of a time saver as even with a chain caked in crap, a few minutes of back pedaling will have to it good as new. For the time and effort it saves, well worth it.