There are no software patents in Europe. I've seen nothing to suggest that European software companies are less competitive. In my daily work as a developer I've not once heard anyone talk about the competition 'stealing our ideas'.

The reason I think software patents are a net negative is that it's the sum of the parts that make a software product valuable. Patenting some of the algorithms used to develop this software product is not going to protect you from the competition in any meaningful way.

Contrast this with pharma where the end-product is simple, often a single easily reproduced compound.