Owning a kitchen design/manufacture/installation business (or 'joinery') for 14yrs.......I'll throw in my 2 bobs....
Personally, you can't beat a custom-made job from a good quality
joiner, although some of the large kitchen manufacturer's are starting to get their act together. Kit kitchens used to be crappy, cheap, lightweight & with inferior chinese components, now a few are starting to purchase quality, european fittings, and using quality Aus-made board (best on market!).
With technology the way it is, there's no reason whay you can't design your own kitchen (get advice if needed), take it to a small-medium Joinery, and they'll supply it 'fllat-packed' with instructions for you to install. I did for clients, and over 14yrs (400+ kitchens, only a small joinery, some do that a month!).....had 2 warranty jobs, which were from harsh wear (from kids mainly), fixed up/replaced within days.
1. Ask heaps of questions
2. Get prices
3. Checkout past jobs, or even talk to existing clients.
4. hardware, find out the brand and research it (you can't beat 'blum' & 'hettich') if the hardware fails, doors sag, drawers break, handles tarnish....you get the drift.
Don't settle for 'kit' looking kitchens, you might find that you actually pay more than you would for a better/personalised job by a tradey that actually gives a s*%t about what they do!
PM if you want any specific info......my brain's full of it (unfortunately), and have archives of info for
fun bed-time reading