i'm finally getting around to reviewing this after i've been using it for about 1 1/2 months...i've been trying to use it for long & short walks and over a variety of grounds to give a complete review...i use it with my city select stroller as i needed a seat for my 3 year old (he got upset when his city select seat was removed to make room for the new baby)...NOTE: I HAVE ONLY USED THIS WITH THE SEAT ATTACHED, THUS FAR...so let's get the negatives out of the way:it is NOT too quick in attaching/detaching...it does take a minute or so...when you attach the straps, you have to pull them tight to get them secure and they click while tightening (they're like teeth)...for detaching, you have to get low and lift up the straps with one hand while loosening the latch with the other...however, it IS doable and not complicated...if you are pushing your stroller & this seat over uneven ground (think big cracks in the sidewalk, rocky (big rocks) dirt ground), you can expect it to tip over...i soon discovered this little inconvenience, so if i do walk on uneven ground i simply hold the back of the seat for stability...side note: i have rolled this up a small ramp while turning, not holding the seat, and it did not tip over...backing up can be cumbersome...think needing to back up in a store aisle or while checking out during a store visit...again, i hold the back of the seat to help steer it while backing up...if you have a rowdy little one who decides he no longer wants to sit in the seat and tries to push back to get out (while buckled), you may find that the hinge that connects the arms to the base of the seat lifts up (think upside down V) and will cause your little one to tilt to the side and/or fall on the floor...be warned...no injuries, just a bit of inconvenience when you're trying to shop without drawing too much attention to yourself and kids...another thing, since the seatbelt is only a strap like that in a grocery cart, said rowdy child may stand and wiggle out of it....oh, and to push my city select with this thing, i do extend the stroller handlebar as far as it can go and still have to stand to the side of the stroller while pushing if i want to walk briskly...i am able to walk directly behind the seat, but rather awkwardly, kind of extending my back...i only do this occasionally...most of the time i walk on the side...i've grown accustomed to it now...ok, so i think that's it with the negatives, so now the perks:you have an extra seat!!! and that is the greatest thing...i absolutely love my city select and would have been sad if i had to get rid of it...this extra seat provided me with a great opportunity to keep 3 little ones aboard and buckled...although my 3 year old can get out of the buckle, he does enjoy getting in his seat and being buckled...depending on the trip, he may or may not stay in the seat the entire time...i've looked for another stroller attachment that compared to this one and could not find one...i didn't just want a standing board as i figured my toddler would get tired of standing and i wanted him buckled as well...this seat is a hit with the little ones...my son and his little sibling fight over who gets to sit in the seat...i have walked on smooth pavement, unpaved dirt (without big rocks) and grass just fine...the wheels have been quite durable and able to roll over small to medium bumps without issue...as stated above, if you're rolling over larger rocks or uneven ground, simply hold the back of the seat...also, although you will more than likely have to walk to the side of the seat, you don't have to walk super slow, but you can walk normal to a brisk pace..finally, i have a minivan and am able to fold my city select with this seat attached...i just recently learned i could keep the front seat attached to the stroller as well and life got that much easier! while storing it in my trunk, i can either lay the stroller flat and put the seat on top or sit it behind the stroller...to fold, you have to tilt the seat back, away from the stroller and fold as normal...being that the city select is already on the heavy side, this extra seat is not too bad with weight...just a bit cumbersome...i'm a woman and i can pretty easily fold the stroller and put everything in and pull it out of my van...nothing is perfect and there is always room for improvement...despite the little negatives, i'd totally make this purchase again knowing what i know because the advantage of having an extra seat without having to buy another stroller is absolutely terrific...in my case, there's no way i was getting a triple stroller so having the ability to get my toddler seated is a major plus...if you're thinking you can jog with this, think again...if you have 2 little ones, you're better off getting a double stroller for that...but this is great for leisurely or brisk walks...