B-smart is 62cm wide, whereas the B-Agile is 58cm wide.

I'd also try the Baby Jogger City Mini GT Single.

and the The Baby Jogger Summit XC too.

www.bestbuggy.co.uk/category/single/baby-jogger-city-mini-gt-single/

www.bestbuggy.co.uk/category/single/baby-jogger-xc-summit/

Ditto with the Callisto, shame it's so long cos I loved the handlebar bit.

I have a B agile, it's very nice, it's pretty much exactly as you say good for walking, light to lift, small fold and comfortable. I live in a fairly bumpy sort of town so particularly wanted 4 wheels (prefer the feel on em) and bigger wheels than the city mini. Whilst I suspect the city mini is maybe better quality in some areas the b agile is cheaper and certainly does the job. The suspension is nice. The only niggle is the seat.. .there is something, some have said position of crotch strap, personally I think it's that the harness is a bit short that makes an older sitting baby/younger toddler look slumped in the seat. I added sit up straps so my toddler can sit bolt upright and still use the shoulder straps, equally you could just not use the top straps.

Unless you want something much more off road, like the things mentioned above then you probably wouldn't go far wrong with the b agile IMO it's not life changing but it looks nice, pushes nice. AH, speaking of the pushing bit the handlbar is fixed at 100cm (I think), I'm 5'8" and find it fine, tiggy who is 5'6" found it too low.

HTH

I think there's two key questions. How old is your LO and also how tall are you / do you like a low or high handle?
The B-Agile has a low handle and is better for older toddlers. The BJCM is better for all ages but has a higher handle. It may seem very basic but it was a deal breaker for me when I used them both.
B-Agile v's BJCM4
B-Agile review and photos

12 mths is def within the age range for the slumping. It depends how upright she would want to sit, you can get around the problem anyway but perhaps I'm a bit overly willing to improvise with webbing and velcro!

Bits defo no problem for the basket, it's quite a good size (but fairly low) for this type of buggy, access is okay due to the curved bar across the back of the chassis (also good for not kicking it). I haven't had anything fall out yet though.

I have had this feeling that the baby joggers are somehow "better" but I don't really know why. I'm fairly sure the suspension and wheels on the b agile are better but possibly the seating position is worse. I also wanted to lose the extra 4cm from the city mini.

Try 'em out somewhere, you can't lose, they're both good. I could easily have it as my only buggy... I don't... but I could!

I've said on this board before that I love my B Agile, but I still can't help thinking I want a BJCM (this is as they're very similar).

Personally I did a pros and cons BJCM vs B Agile, and the B Agile won on almost every count. I prefer the fabric, it's softer and doesn't feel as cheap; I prefer the wheels; it's easier to get in the basket; I prefer the foam on the handle rather than the rubber on BJCM; the 4 wheels felt more stable (the BJCM4 wasn't available near me at the time I bought it). And it fits in my boot where the BJCM wouldn't (again, ). But it's not a BJCM.

Still love it though.

I use it without the shoulder straps, so DD can sit bolt upright. She's never been that keen on shoulder straps anyway. Once she could sit up at around 7mo I had to lengthen the harness on the B Smart so I could just do it up around her waist, and not put her arms through.

The B Smart is still my every-trip pushchair. The B Agile is my car pushchair.
Me and DH like low handles as it turns out - I'm 5'4ish and he's 5'10. We adjust the handle right down on the B Smart.

HTH

I just got a b-agile after a lot of deliberation and like everything about it except that the seat back isn't upright enough (if someone can enlighten me as to how to do sit up straps I'd be grateful!). My almost 20 month old slightly slumps unless i liberate her from the shoulder straps and put a cushion behind her back. It's very smooth and light to push and manouevre, easy to fold, looks well made and not too expensive. Good on rougher terrain but small and light enough for shops, public transport etc.

I just got a b-agile after a lot of deliberation and like everything about it except that the seat back isn't upright enough (if someone can enlighten me as to how to do sit up straps I'd be grateful!). My almost 20 month old slightly slumps unless i liberate her from the shoukder straps snd put a cushion in her back. It's very smooth and light to pushband manouevre, easy to fold, looks well made and not too expensive. Good on rougher terrain but small and light enough for shops, public transport etc.

Either one long piece of webbing with velcro sewn on each end(rough bit one end, smooth bit other iyswim, these two ends will then fasten together and pull the seat more upright). You'd then wrap round both sides the frame under the fabric and fasten as tight as you want. You'd have to take this off completely to recline the seat though. Or two shorter bits that stay wrapped around the frame either side then velcro together in the middle when you want it sat up and hang loose if you don't. I used poppers where each one goes round the frame but it was a bit of a faff putting them in the webbing strap, velcro would work. A no sew option would just be a long old piece of velcro quite overlapped so it was strong enough to hold the seat up. The worst that could happen if it came undone is the seat reclining an inch or two so nothing major!

I ready somewhere mutterings about baby jogger having removed their sit up strap on this years model but can't remember actual facts... Tipping risk was mentioned. I don't find mine tippy with the seat really upright but perhaps worth bearing in mind. Suppose not using the shoulder straps kinda results in the same sort of risks anyway where the child is free to lean forward etc.

Hope that helps. I can't seem to find a good way of explaining it so it might not be clear!

Very helpful, thanks a lot!