I have the Out n About double (version 4). I like it ...don't love it but I think that's more to do with the fact it's a double pram and as the man in the pram shop said to me about double prams, 'they're all about compromise'. And when I was looking around I would say that is fairly true.
I wanted a side by side as I found the stacker prams (ie the Uppababy double, Phil & Teds or icandy) too heavy for my back.
I think it's pretty good value, when you consider the price of a number of the doubles on the market. I got the pram, newborn insert, foot muffs, under pram storage thingy and the non puncture wheels for just over £500. It's worth shopping around for them as they seem to go on sale at various shops.
To avoid the puncture issue, I immediately purchased the puncture free wheels you can get with it (I think they cost about £45) so that has never been an issue.
The turning on the pram is brilliant - it makes a tighter turn than my single (a Bugaboo chameleon).
One issue I have found is the weighting - if you hang a bag on the back of the pram or fill the back pockets it becomes very 'back heavy' and you do need to be careful of it wanting to fall backwards. It never actually has so far but when you go up and down pavements etc you can feel the pram lean back quite a lot.
Depending on the age gap between your children, the side by side factor does enable them to lean over and give each other a whack! My eldest has nearly taken the baby's eye out (only a 12 month age difference).
For the newborn I didn't buy the bassinet, I used the newborn insert (£20 for the insert vs £100 for the bassinet) which served me well. As the seats can lay flat and are quite enclosed not buying the bassinet was a good move.
I've actually never folded the pram down, except when I was trying it out! (I take 2 single prams + partner or a sling + pram if we are going out via the car - rare as we are zone 2 London). It is a big fold down, it's quick and quite simple to do but it's a big pram, it's not compact. Be sure to check it will fit in your boot.
We are London based and so far I haven't had any issues with it not fitting in doorways etc. If you lived in a town with lots of old buildings you'd struggle. That said, it certainly isn't the widest side by side. It's only a fraction wider than the narrowest side by side on the market (the Mountain Buggy Duet).
The seats are nice and roomy. A number of the side by side prams have very narrow seats made for narrow bottoms! I worried looking at some of the narrower seats that my children would grow out of the pram before they were ready to walk. I also thought with some that by the time you added winter wear it would end up very squishy.
One pram shop told me the Out n About is owned by the same people who make the Mountain Buggy. When I compared the parts on each pram it certainly looked to be true, they look very similar. The Mountain Buggy starts at £580'ish vs high £300s/ low £400s for the Out n About.
If a double pram is what you need and you are not taken with the stacker prams I'd say this is a good option. Hope that helps, x