[Seaside] Should I become a Seasider?

[AA]

You can develop complex applications much more rapidly in Seaside than in most other frameworks.  Prototyping and iterating are very straightforward, and there's a good choice of relational or object databases to work with.

GLASS is an 'enterprise' framework, with a corresponding level of support, so this is one reassurance you would be able to provide to corporate customers.

In addition, as Sean already mentions, Smalltalk developers are not common, but their quality certainly makes up for it.  If someone had to pick up after you, a Smalltalk code base is quicker to come to grips with than, say, something made in Java... ;-)

Amir