Have a very good friend that I have worked with for the past 2 years who happens to be a US Army WO - Commissioned Warrant Officer 3. It took us all a few weeks to work out exactly what the hell that meant when he first started, but essentially he - and all other CWs (2-5) are classed as junior officers, and are treated as such. They do not salute fellow JOs on unit or call them sir and it's a system that works fine with us. However, by the time they get to CW 3/4/5 they have that much experience they are usually 'equivalent' to Sqn Ldr / Maj.
From working with the US Army in Telic, I found the biggest problem came when you had Brit WOs / Sgt Majs who quite rightly, are at the top of the tree as far as we are concerned, but this one particular WO was relegated to organising cleaning rosters by the US Army as they didn't understand the difference between Brit / US WO ranks. That one was very quickly sorted when said Brit WO (almost 20 yrs experience) had a rather loud quiet word with said US Army Sgt Maj (approx half that experience). At least there's one Sgt Maj in the US Army now knows the differece
The thing to remember is that the CW scheme is usually for tech specialists - pilots, intel etc and they go through their own Warrant Officer Candidate selection / school. Although they fit in somewhere in the JO bracket, think across to PA type specialists is about as close as I can come up with an equivalent status in the RAF.