I spent ages researching travel systems (and getting quite frustrated!) and this is what I found:

Steelcraft:
- the Safe n Sound Unity Capsule is made to fit the Profile stroller
- there is a Cruiser capsule that is made to fit the Cruiser stroller (I think this may be exclusive to Target)
- there is also a capsule that is made to fit the Strider stroller

Peg Perego: there is a Peg capsule that fits all of their strollers

Babylove you have already found

Then there are certain strollers you can buy a car seat adaptor for, that will enable the stroller to take a Unity or Peg capsule. You can do this for Baby Jogger, and I think Bugaboo and Quinny.

I thought they were all pretty good systems. In the end for me it came down to which stroller I preferred.

Hope that helps!