Hello, we use ultragrid with ultraGridFilterUIProvider in win forms app. We have big data (100 000 rows ). Our filters work slowly. See small example  in attachments.

      public Form1()
        {
            InitializeComponent();
            DataTable dt = BindData(100000);

            ultraGrid1.DataSource = dt;
        }

        DataTable BindData(int k = 100)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("Column1", typeof(string));
            dt.Columns.Add("Column2", typeof(long));
            dt.Columns.Add("Column3", typeof(DateTime));

            for (int i = 0; i < k; i++)
            {
                switch (i % 5)
                {
                    case 0:
                        dt.Rows.Add("string" + (i * i - i), i * i - i, DateTime.Now.AddDays(i));
                        break;
                    case 1:
                        dt.Rows.Add("row" + (i * i * i - i), i * i * i - i, DateTime.Now.AddDays(i - 7));
                        break;
                    case 2:
                        dt.Rows.Add("text" + (i * i * i - 10), i * i  - i* 17, DateTime.Now.AddDays(i + 17));
                        break;
                    case 3:
                        dt.Rows.Add("sample" + (i * i  + 18), i - i * 3, DateTime.Now.AddDays(i - 11));
                        break;
                    case 4:
                        dt.Rows.Add("data" + (i * i + 2), 10 - i * 9, DateTime.Now.AddDays(i + 3));
                        break;
                }
               
            }

            return dt;
        }

        private void ultraGrid1_InitializeLayout(object sender, Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs e)
        {
            e.Layout.Override.FilterUIProvider = this.ultraGridFilterUIProvider1;
            e.Layout.GroupByBox.Hidden = true;
            e.Layout.Override.AllowRowFiltering = Infragistics.Win.DefaultableBoolean.True;
            e.Layout.Override.FilterUIType = Infragistics.Win.UltraWinGrid.FilterUIType.HeaderIcons;
            e.Layout.AutoFitStyle = Infragistics.Win.UltraWinGrid.AutoFitStyle.ResizeAllColumns;
        }

Its very important for us. Thanks