As a parent with an 18 year old currently just passed his aptitude for pilot and his AIB for the FAA and considering whether the AAC might be fun as well, I think I have some experience to offer. Especially since I spent 20 generally very happy years in the RN myself before leaving to find new challenges.
Am I happy my son is committed to starting a career in flying (or any other discipline, for that matter) with the military? Absolutely 100%. Do I think the services (whichever) aren't what they used to be? Gone to the dogs - but they were going to the dogs in my time, my parents' time, my grandparents' time...................
Whether my son ends up in the Navy or the Army (the RAF doesn't seem to appeal, for some reason - can't be me, surely) as a long term career seems to me entirely irrelevant at 18. What I do know is that he will work hard, have a whale of a time, learn a marketable skill and, most important of all, learn life lessons such as leadership and decision-making under pressure which will make him a very attractive proposition should he decide to leave later on and pursue a career outside the military.
I envy him his youth and his chance to enjoy all the things I enjoyed at his stage.
And as for those who whinge about workload and working hours, words fail me - don't think it's any easier outside. The separation may not be there but if you really think anybody is going to offer you a challenging job with real responsibility (and therefore a decent salary) without demanding blood in return, you have a sad awakening coming. Failures to meet the standards demanded in the Services may occasionally have serious consequences, of course, for the individual and for those he is responsibile for. But generally those failures are not life-threatening, are spotted early and dealt with by encouragement, closer supervision, retraining etc. They are not met with a sudden invitation to clear your desk and return the company car keys.