I have a couple of Typhoon manual life jackets which I paid about £48 each for they are a nice simple design but imho the quality of the inflatable bladder seems very poor and which is very similar to those kids water wings from the 80's era you know that thin plastic stuff.
Anyway some time ago whist checking to see if they would stay inflated after use, one of them had a leak which was a very fine pin hole directly behind the gas bottle which I presume was caused by the gas bottle banging against the bladder after falling off the seat on the rib or being dropped on the floor or whatever. Not good
I also have a more expensive Crewsaver crewfit 190n LJ the bladder is a bit better quality but not much, but the gas cylinder does have a neoprene sleeve which covers over it .( Much better idea )
however!! I have just purchased a re arming kit ( don't ask )
and while fitting it there is a crappy little and very brittle green plastic clip which goes over the manual pull spring which broke while clipping it on
How do some of these LJ get passed for the ce mark ?? they appear to be poorly built and not very hard wearing for normal boat use, I am not sure what LJ these rib ride company's and commercial users use but they must get some stick, more so than from us leisure users. Does the quality actually get any better the more expensive you go and how much do you have to spend to get a half decent LJ.
I personally would feel a lot safer wearing a PFD at least there is no worries if it will inflate or stay inflated when you really need it.
p.s. make sure that you check and inflate you LJ on a regular basis.