It very much depends on what you want to do in your future aviation career/interest.
PPL is fine, generally expensive to go beyond and comments about bad habits are all true. That said, all flying experience is valuable and any FTO worth anything will be able to train you to do things 'properly'
Gliding (civvy) is relatively cheap, and from my experience with various civvy gliding organisations, hand out qualifications as if they were selling raffle tickets! Don't get me wrong, there are some VERY good establishments and pilots out there but for every good one, there are MANY crap ones as well. As such, many people have little regard fot civvy gliding.
Gliding (Military GSA/VGS) is another cheap way of flying, indeed depending on circumstances, I believe help contributre to some expenses. If the RAF/RN is where you see yourself heading, then this is a ideal start as all flying training is carried out by instructors who have been endorsed by CFS in the RAF. Even if you want to go civvy and fly some heavy metal, it is still a cheap way of getting some decent training. Admittedly you will have to contribute quite some time to the organisation to progress through the system.
The options are there, only you know your circumstances and can decide.
Good luck
