The more I use it, the less I like it. It's big, bloated, unwieldy, cumbersome, and annoying. There are so many inconsistencies with it, both in the interface, and the development, that it's a mess to work with. And that's without even touching on the problems of developing something for use with both the Lotus Notes client, and from the web.
Here's an example. In a recent project, I had a fairly long and involved form. In case someone reached a point where they simply wished to clear the form and start over, I have a reset, or clear, button on the form. It took me 4 hours to get that button working. And it still doesn't always work right. If this were a web form, I could have that button done in 2 minutes. If this were a standard application, I could have it done in 20 minutes or so, depending on the language and complexity. But 4 hours, from a "rapid application development" environment?
Every time I discover a new feature, I find myself not being pleased that it exists, but disgusted with how poorly it's been implemented and designed. The whole thing has the feel of a good idea that was implemented by incompetent fools.