With 37signals announcement of the company restructure they are going through; concentrating on Basecamp and eventually getting rid of everything else, something I saw in a Joel Spolsky Post years ago in regards to building your own tools still rings true.
The best advice I can offer:
If it’s a core business function – do it yourself, no matter what.
Building my own tools is a theme for me this year. 37signals just reminded me how important it actually is.