Should You Use PTFE Tape?

[Tayters]

I've always thought PTFE tape breaks down when in contact with oil therefore no good on a refrigeration system, so I got a tube of blue 'DiversiTech' sealer.
"Never use that stuff with R404a as it eats through it. Use PTFE."
I've seen it on flare nuts (that's a bit pointless methinks) and oil level sight glasses on scrollers and never seen a leak from one. The old school boys swear by it so I suppose they're right but I'd like to know what the masses reckon.

[monkey spanners]

Is that blue stuff from Diversi tech no good then? got a free tube at the RAC show so maybe i won't use it now!

I've been using 'Trublu' stuff from RPW without problems but i think it also has ptfe in it.

There are some locktite products which often get recommended here but i forget the numbers, am planning to try some when the trublu runs out.

[Quality]

Locktite 577 works every time

[ActiveEngineer]

So should we be using PTFE tape or not, I use it on all my fittings

[ICE/RUNNER]

I use PTFE tape, tried some of the loctite sealers was not to confident with them so went back to tape yet to have a leak plus you don't need a permit to use it on the site i work, ever thing right down to the leak spray has to have the correct paper work before we can use it. I know safety is important but it can be taken to far.