I think it's quite simply that Hauck are a cheaper brand than say Britax.
It's easy when you see the two together that the quality is very different. The Britax fabrics are thicker and better quality. Things like the brake pedal are better quality. The fixings are better etc. What they do is very similar ie child positions but the major difference which won't affect you is that the top on the Duett is the baby space which doesn't really work with a toddler underneath, whereas with the B-Dual the baby really is best underneath with the toddler on top. The other difference is the ride. It's much harder with the Duett and you do feel it. There didn't used to be a raincover but the B-Fual one fits great. It's very good though - but there hasn't been much of a price difference between the Duett and B-Dual so for me there is no question which is better value for money at the low prices. But I know width matters to you and if that's more important then that's what really matters. There's not much in them though, and if you don't ever see a B-Dual you will never know what you are missing! It does the job of carrying two older children well plus has basket space :)

I should have said Britax B-Dual at the start :) I hate not being able to edit posts!

I'm feeling a sense of deja vu however... I have a duett (top reasons - cheapness, width and the b dual's slouchy seats for older kids).

For me it is a stop gap. It's okay but not top quality, I find the ride is on the hard side of acceptable but we have lots of cobbles and bumpy pavements etc. Would agree britax frame, fabrics and wheels are better quality as also have a britax b agile single and there is a very different feel. The britax ones all have proper suspension to the frames so are nice and bouncy to push, the Duett doesn't have this, just sprung wheels. I'm happy the frame of the Duett is strong as I have used mine on emergency occasions for 22kg 4 yr old in the lower seat, which obviously quite significantly exceeds the weight limit. It's entirely possible I will pay for this later and it will break! It's also reasonable to push as I could do this 7 months pregnant without killing myself.

Tiggy is also right it's impossible to use with the baby in the top seat, which is the carrycot convertible one, they really have to go the other way round which is illogical because the lower seat is fine for an older child but not at all supportive for a baby nor does it go flat. Personally I'd be happy from 4-5 months with a good kind of body support and footmuff to provide the support the seat lacks but people will vary significantly with what they feel is acceptable.

If I wasn't obsessed with width (and a cheapskate) I'd have chosen a b dual but the extra 10cm were never going to happen in my life. Duett was £220 when I got it, have added a graco soft cot (£8 ebay) on lower seat and b dual raincover (£7.50 from tesco) so a total cost of £235.50.

Rendering all the above slightly pointless clearly I will dump it the instant the oyster max comes out!

LOL I love the fact that cost is so important to you ihateparties but you are happy to throw all budgeting out of the window for an Oyster Max!! LOL You are funny :)

Oh I shall sell something.. .the car springs to mind right now!!

Haven't you got a baby to have???? Dont do anything too hasty right now!!