Well, I can't speak to Rambler but have more Cassies than I can count. Truly my go to bag.
I had one Parker awhile back & going based on memory, the Madison is an update in the best way. Correct me if I'm wrong but I think the Parker had concave sides which cut into the space on the interior. I believe also did not have a full length back exterior pocket. Just a smaller pocket which did not really fit my phone without a lot of shoving lol. This one is just spacious with tons of compartments in organization. I have another Madison that I posted a lot of photos on. I'll try and find that post and notate it here.
EDIT: Posted on What
Coach Bag Are You Carrying Today on April 24th, post # 23,779.