What’s a good Exchange compatible mail archiving solution?

We run SBS2003 with exchange and have about 50 users. We’re looking at adding some mail archiving/retrieval software for compliance purposes.

I’ve had a quote for Zantaz Enterprise Archive solution from a provider who wants about ?8.5k($16k approx) to setup and maintain for the first year and then a further ?2.5k PA ($5k approx) to maintain thereafter. This does not include any storage hardware we may need. I think this is a little steep to say the least!

I’ve just found GFI mail archiver after reading good reports about GFI’s anti spam program. This is much cheaper at $1100 for 50 users.

But is it any good? Are there any better solutions?