Altova has released a 64 bit version of its MissionKit tool suite. It is supposed to give you a performance advantage, especially when dealing with huge XML files. Altova says that this version can help you edit XML files that are a couple hundred megabytes large.
This latest update is Version 2010 Release 2. You can get the update for free if you have a subscription. Otherwise this thing is going to cost you a bit of money. MissionKit is composed of a number of tools such as the famous XMLSpy XML editor. I know the developers and testers in my company all want a copy of XMLSpy. The other tools may not be as important.
We process relatively small files in our production environment. So for now we run a 32-bit version of XMLSpy. However things may ramp up once the customer gets comfortable with our XML loading software. Maybe a copy or two of MissionKit 64-bit is in order for next year.