If you are upgrading or have just upgraded amr-users, please ‘rebuild nice names’ immediately after upgrading.
The improved (I hope) query uses the wp_query facility as much as is possible depending on the nature of the fields you want to extract. To do this, some cleverness was required – the cleverness begins in the nicenames.
In fact it is a good idea to rebuild this any time you add other plugins that create user data or add possible field values to your existing data. Remember unless there is a meta data record with a value in it, the plugin will not ‘know’ about your new field, so when adding new fields it is helpful to have a test user with a value for each field.
The update also moves some of the hard work away from php towards mysql. Very large user meta databases with very complex queries may find this a bit of a challenge for th wp-query logic!. Please do let me know at the forum if this happens to you. It is helpful to know the sorts of things people are trying to do. Already some ‘interesting’ requests have come through!
Please describe the type of data and the type of query as well as you can. The forum is the best place for now.