well, after almost a month of using aptana and eclipse at our offices we've now uninstalled dreamweaver from our machines - we have also started using subversion which is fully integrated into eclipse (if you get the subversive plugin) and this is going to make a huge difference to our work
the features of aptana really do outshine dreamweaver - there are a few areas that it could be improved such as a wyswiyg editor - its very useful for jumping about the code in dreamweaver. On the whole, no regrets on making the switch!