There are quite a large number of questions I would ask if you said "I want to buy a rollator". Height and weight obviously play a big factor and cross quite a number of models off the list depending on the answer. The next question is 'where do you want to use this walker?' People that do a lot of outdoor walking tend to find the larger 8 inch casters a better option for stability. And the third question I would ask is whether cable-brakes are an issue- 95% of rollator purchases I've overseen have been cable types: compression walkers (or push-down brakes) have their place, but aren't as versatile as their hand-brake counterparts.
The Pride 6" rollator is one of the best walkers on the market today. It covers all the bases for a standard 'bit of everything' rollator. To start with, as the name implies, this walker has 6 inch wheels. Although larger wheels can be better outdoors, this size isn't so small that it has any major issues outside. Furthermore the smaller wheel reduces the total weight and makes the turning radius a little better. The curved backrest is comfortable (and removable too which makes transportation easier) and the deep padded seat is great for short-term perching. As far as storage goes, beneath the seat there is a vinyl bag instead of a metal basket. This allows three things: the black vinyl hides the possessions, it catches loose objects (such as coins and keys) and- most importantly- you don't need to remove this to fold it. Many of the rollator-users end up losing their baskets or crushing them in transportation.
Check out this great rollator today. Don't be fooled by those super-cheap 'supermarket' walkers (you know who I'm talking about). Their cables will break within months and you will be buying another walker VERY soon. Trust me.