If it was me I would start off with a proper think about what you will be doing day to day. Whether you drive everywhere so need to fold and lift your pushchair several times a day, or take public transport so the pram needs to be small and/or foldable whilst holding the baby. If you walk everywhere then a big basket and more robust wheels might be more important than size or how it folds. All of that sort of thing.
With dc 1 I lived in london zone 6 in a first floor flat out in the woods (sounds bizarre, was bizarre) and had to drive or take a very sparse bus service to get anywhere. I bought an Icandy cherry that was light but didn't fit easily into my car boot. As a result I used a petite star zia a lot because it was very much easier in and out of the car, plus ds wasn't a big fan of the carrycot anyway and after that was more unsettled by facing me than facing outwards illogical baby that he was.
By the time I had dc2 we lived in a house in a totally different city and walked everywhere, the cherry had broken so I got a bugaboo gecko. Brilliant for walking with, great with a buggyboard, made me want to cause it injury on the very odd occasion I folded it. Dc3 we used a tandem as dc2 was still young.
My needs were very different as my circumstances changed. If I was starting again in my dc1 circumstance I would buy a babyzen yoyo 0+ and a fixed 0+/1 rear facing car seat (such as a britax dualfix, cybex sirona or hauck varioguard). If I was starting again in my dc2 situation I would buy an easywalker mosey.
Re the individual models
Pioneer - nice I think, pretty wide, smallish seat, not sure how easy to manoeuvre. Possibly good for lots of walking if handling is good.
Wayfarer - hard to turn, wheels not the best quality but nice and narrow. Not ideal for loads of walking imo.
Bee 3 - nice and compact, folds rear facing, again not what I'd choose for lots of walking or any terrain other than pavement. V. Expensive now for what you get considering other options available.
Cam - classic choice, lovely to push, pain to fold, basket issues with carrycot on, not compact for public transport. Great for walking.
Oyster 2 - solid choice, very practical all rounder, I don't personally like the push but it isn't bad.
Scoot/scoot2 - like it, bit heavy to push and lift but size and fold pretty practical. Another I wouldn't choose for a walking lifestyle.
Literally everything has mixed reviews. At least in part because people have such different needs from their pushchairs.
*disclaimer - I hate umbrella folds and over 3 dc have never switched to one, although I have switched to smaller sized non umbrella pushchairs,