Here's an interesting post from a Java guy trying to decide between Ruby on Rails and Seaside. He has quite a few interesting things to say concerning the shortcomings of Ruby on Rails, and how well Seaside handles that complexity with ease.
He also has a few complaints about Seaside, most of them valid. Seaside still isn't the full stack solution that Ruby on Rails is. We still have to handle object relational mapping, something Ruby on Rails gives you for free. Nor does Seaside deal with object validation and errors, I use Magritte for this. Magritte rocks, but I'm not sure the average guy trying out Seaside will find it, or learn how to use it. From an outside point of view, Ruby on Rails looks like a much more complete solution.
We have Glorp, which can do this, but only against Postgres Sql in Squeak. Nothing against Postgres, but seriously, in the real business world, it's either Microsoft Sql Server or Oracle; and it's also usually a legacy database, so we really need something like Glorp for those databases, because something like ActiveRecord is just too brain dead to work.
Most of the schemas I have to work with suck, and can't be changed because people used the database as an integration point for multiple apps (God I'm tired of seeing people make this mistake). Doing a simple class = table, object = row mapping just doesn't cut the mustard for legacy development against existing databases.
Seaside is far more advanced than Ruby on Rails, and is a much better web framework for doing anything complex, but we're still missing the market on CRUD apps. CRUD against a popular business database is still far too difficult using Squeak. I'm sure Visualworks has far better database support, but I want something free... I want Squeak, I want Squeak to work with Sql Server, I want a Pony... :(