If it fits under your tank and holds water - most likely it will work.
It all depends on what you want to put in the sump, baffles or dividers and such.
Glass or acrylic sumps are much easier to partition in to chambers and I think they look more professional. If you're handy with some basic cutting tools, and are interested in DIY - these are the best in my opinion. Sometimes space is limited though.
Rubbermaid containers are available in a lot of different sizes, are very cheap and work okay if all you want to do is add water volume, and hide some of your equipment. You still gain many of the benefits of a sump - but it will look homemade, and these containers are much more difficult to install dividers into.
Given your requirements and what you want to do - either way works fine.
What size tank you have ?
What are your main plans for the sump ?
How much equipment you have to hide down there ?