There are only three countries that currently use the Alternative Vote to determine their legislative elections- Australia, Papua New Guineau and Fiji.
This isn't a point against AV but it does make it harder to assess what the actual outcome of AV would be as there are very few countries to look at to compare with. Based on Australia it seems like minor parties won't actually gain any more influence than in FPTP so it is unlikely to result in more frequent coalition governments than we have now.
Sunday School's out forever in Kettering
2 minutes ago