Firstly I'd like to apologise to the people that I offend in this post..sorry! Also note that I'm generalising on the whole as stocking Rainbows could mean into existing Lochs/ stillwaters or include the rise of the man made fishery.
I'd love to have lived and fished many years ago when the rivers and lochs were brimming with large wild brownies. I'm sure we've all seen photo's of catches such as those featured on the likes of the Loch Leven bothie walls, where a group of flat capped pals display a days catch which would have kept me satisfied for many seasons - or maybe even a lifetime. Times have changed and attitudes must change accordingly.
IMHO Rainbow Trout (Blue, Brook, Tiger, etc. included) - properly managed - do have a place in our current fishing environment. Their ancestry is impressive, they can be caught on all standard Brown Trout/ traditional methods, they fight hard, look good & most of all they rise!
The unfortunate thing is that the advent of 'Put and Take' fishing has created a new species of angler who view fly-fishing slighly differently than 'the old sweats' who typically served an 'apprenticeship' on a river, loch or both.
I could spend all day citing tales of badly handled fish, drunkeness, litter, foul language, severe lack of ettiquete (does it not piss you off royaly when you can not cover a 180 deg. casting arc because some twat sets up camp 10' from you 'cos you've just had three fish in ten casts?) but lets concentrate on the positives.
They provide the means for a newcomer to the sport of having the real chance of catching a nice, hard fighting trout.
They allow the elderly (or young)/ disabled/ infirm, easy access to a wider range of fly-fishing venues.
They can help releave the fishing pressure on rivers and therefore natural stocks.
They increase the length of the fishing season.
I'm going to end (as I'm boring myself) by saying that I would like to see the fishing fraternity getting their heads together and promoting a change in attitude towards this fish and how we fish for it.
If I had a small 'personal' stillwater I'd stock it with 1/2lb rainbows and fish with dries and buzzers
I await your replies!?