Here's a paragraph from a register.co.uk report by Gavin Clarke on a Sun/Oracle joint offering to small and medium size businesses:
Pricing starts at $8,270 for the Database Pack for up to 100 concurrent users, with the Sun Fire V20z and Solaris but without storage. With storage, the bundle starts at $15,765. The similar Linux pack starts at $8,589 without storage and $16,084.
That's a $319 premium for Linux over Solaris - ok, if you're used to paying for Microsoft's per client licensing this is like getting the hardware for free, but still where's the Linux advantage to justify that $319?