Now there’s a wonderful can of worms you are trying to open!
As already stated it all depends on the level of training you get, & what you want out of your diving.
I belong to an independent club that conducts its own training; being independent we have had people join us from various training organisations (BSAC, PADI, SAA, & CMAS) & others who have joined us with no experience & trained with us.
We have come across good & bad from all of them, we have had people join the club with advanced certificates & they couldn’t swim one length of the pool, while others have come with minimum training & been very good.
You may find some BSAC divers are a little bias against PADI we have all heard the jokes (what does PADI stand for? Put Another Dollar In or worse still is Pay And Die Instantly) and this sort of thing has obviously caused some resentment between PADI & BSAC.
I personally have been through BSAC sport diver, PADI open water & our own clubs training so hopefully I’m not bias in any way.
The thing to remember is 6 months of BSAC training (of 1 or 2 hours a week) is not a lot different to 4 full days with PADI. The problem seams to come from people doing their training while on holiday, some have told me they got their open water ticket after only 1 hour in the class room followed by 2 dives. (One of these said his first dive was at 35metres on a wreck)
Many of our members who joined our club after training with PADI have said they like being part of a club & liked being able to get in the pool every week to build on their skills (they found most PADI clubs were just meeting places to talk about diving). But a club atmosphere is not to everyone’s taste some people just want to get on a charter boat & dive, while others like to dive & socialize as much as possible.
As already stated PADI certificates are accepted all over the world, but then again so is BSAC. We had a funny experience a few years a go where someone joined our club with a PADI open water certificate he got a couple of years a go, he hadn’t been diving before joining our club & after he finished our training he went to the Red Sea on his own to go diving. He went to the dive centre & showed his PADI ticket & said he wanted to go diving, the woman looked at it & said this is quite old have you been diving since getting it. His reply was “yes I belong to an independent club but you won’t know them” she then asked if he had his logbook to prove he had been diving. As he took it out of his pocket she laughed & said “Oh Swanley Sub Aqua Club that will do fine” he said but you haven’t even looked at it she said “I don’t need to, I started diving with them years a go & know their standard of training & if you can get through training I know you wont have a problem here!”
So to summarize:
If you want to go diving quickly & don’t mind paying for it; PADI is the route (but avoid anyone who tells you “it only takes a day to get your ticket”) PADI open water should take 3 to 4 days, the first 2 days are split 50/50 between the classroom & a pool. The second part is spent mainly in open water (usually 4 dives over 2 days in the UK but this may be done in 1 day if in warm water)
If you are not in a hurry & don’t mind training through the winter to get ready for that all important holiday next year then I would go for joining a club.
The decision is yours but please do remember dive within your limits & keep it safe!