My main reasons for choosing Koha is:
1. Custom interface – the fact that I can customize the OPAC interface and the administrative interface is really important for me.
2. Development and implementation cycles -It is also great to follow the development from question to implementation. The openness and insight is one of my main reasons for leaving the proprietary system world behind.
3. LibraryThing for Libraries. The announced close ties between Koha and LibraryThing for libraries is just what I want for my library. The richness of tags and comments will make my catalog so much more valuable for the students and employees of the naval academy.
4. Cost – Yes I know open source is free as in free kittens, not free beer. But to change a system usually costs a bundle. With Koha I could both test locally and experiment before I made a choice. The desicion was more informed than it has been at any other time in my career (and I have changed systems about four times in different workplaces). And I’m not tied to one service provider, I can move my Koha installation anywhere I like and not be stopped by “business restrictions”.
5. Community – The Koha community is worldwide and welcoming. Just look at the comments on the first Koha post:-) I love the idea of open source and the community around Koha. That I have something in common with librarians in New Zealand, USA and France is just awsome.