I soooo wanted a MB when I was looking, they are great & really sturdy. If you can afford one then I say go for it!!! I love the Black & White one. We couldn't afford it & have since made a friend who flys in & out of NZ for work, so I could have got him to get it for me cheaper....oh well. They don't have the bar, but apart from hanging toys I find the bar a bit of a pain anyway. Also most prams ATM have padding over the bars etc so you can't hang toys anywhere really.
I know someone mentioned they have not toddler seat & the lady in the baby shop when I was looking told me they didn't have one either. But I have two friends up here, both with a MB & they both have a toddler seat...so there is obviously one that fits the pram.
One thing to consider is the MB is very exp & it usually doesn't come with any extras. So it's more for the insert if bubs is going to be small in winter, sun cover, rain cover, bar etc are all at extra cost. Also I would think about the weight, where we live most people walk as everything is close in a small town so lots of people have a MB as they don't go in & out of cars with them. But they can be very heavy if you are forever in & out of the car. Same goes with the basinett, that is an absolute pain to put on & off all of the time, especially for just short trips.

I myself bought the Valco Runabout Tri Mode & don't have a bad thing to say about it & living where I do I walk everyday!! The insert was fantastic when Charlie was first born as I didn't have to strap him in & he was soooo snug. This saved me having to use the basinett & waste the extra money on buying one as they have to be put on & off each time you pack the pram up. The insert on the Valco is different to most as it goes under the bar & is sort of like a sleeping back, it's fantastic. I got all the extras needed in a package deal & still didn't cost as much as the MB.

As for fitting through things like the supermarket checkout, most prams dont! I don't know why they don't make these places more pram friendly....it really annoys me. We live in baby capital just about, like most mining towns & there is only one lane most prams fit down at Woolworths, yet they still don't open it everyday...so like everyone else I just put it through & walk out & around to pay. That's no big deal & most people here do that. If I can't fit in a shop, then they lose my business & they should think about making things more baby friendly as it's not just my business lost.