I use it. It has thousands of addys. Most of the SW addy's on StarTiger are on Wattographs. If they aren't...they end up there thanks to SW collectors. However, it is really useful in comparing responses and response times.
If you collect numerous autographs, it might be worth it. If you only collect SW, then you could probably get by with Wattographs and other SW related sites. Most of the addy's here on the Spy are cross-checked with StarArchive and Wattographs before being posted as a project. However, you really need a full database to have an up-to-date impression of how the responses are coming.