I LOVED, LOVED, LOVED my Kolcraft Universal car seat carrier. It's got a huge basket that's easy to access... the wheels really hold up.......and it's easy to unfold w/ one hand... (and fold up) It was also the only thing that fit in the trunk of my tiny Toyota Yaris. I am so sad that my son outgrew his infant carseat... now we use a tiny Baby Trend stroller... and another Kolcraft little stroller.
Oh yeah... I forgot... there are 2 cupholders and a little compartment to place your keys, etc... All I added were two Mommy hooks and a stroller bag I made and I was set!
I tried the Maclaren Easy Rider and thought I would chop off my finger opening the thing....and it was SOOO wide... I returned it... I bought the Graco carseat carrier and returned it because I couldn't get to the basket w/out removing the carseat... Then- I returned my carseat, bought the car seat carrier and tried every carseat in Baby's R Us until I found one that fit. (Our Chico Keyfit 30 fit like a glove) It doesn't snap in, but this thing didn't go anywhere.... The platform held it up slugly in between the two bars... They have a strap you can use if you're really worried, but we never did...
I have a frame you can have for free if you want. The basket and cupholders are missing. (I sent the basket in to get a free replacement after 1 year of use...) and took the cupholders off to install in another stroller... but- you can at least take it to the stores and try out carseats. It's perfectly funcitonal... but doesn't have the accessories.
Just PM me if you want it... I live in Williamstown. (My son is 13 months... we no longer need it... and have a replacement for if we ever have another child)