The BorderLocation property of ListViewItemStyle seems to either not be working correctly, or is severely limited in its capabilities. Although the Location enum is not marked with [Flags], the values 0, 1, 2, 4, 8, 15 seem to imply bit flags that should be able to get OR'd together. However, when trying to use Location.Top | Location.Bottom, the result is NO border at all.
Example:
    public class BorderLocationExample : ContentPage
    {
        private readonly ListViewItemStyle BorderAll = new ListViewItemStyle
        {
            BorderColor = Color.Blue,
            BorderLocation = Location.All,
            BorderWidth = 8
        };
        private readonly ListViewItemStyle BorderTop = new ListViewItemStyle
        {
            BorderColor = Color.Blue,
            BorderLocation = Location.Top,
            BorderWidth = 8
        };
        private readonly ListViewItemStyle BorderTopAndBottom = new ListViewItemStyle
        {
            BorderColor = Color.Blue,
            BorderLocation = Location.Top | Location.Bottom, // <-- DOESN'T WORK !!!  These items have NO border at all.
            BorderWidth = 8
        };
        public BorderLocationExample()
        {
            BackgroundColor = Color.Gray;
            var items = new ObservableCollection<string>
            {
                "Item 1",
                "Item 2",
                "Item 3",
            };
            Content = new StackLayout
            {
                Orientation = StackOrientation.Vertical,
                Children =
                {
                    new RadListView
                    {
                        ItemsSource = items,
                        ItemStyle = BorderAll
                    },
                    new RadListView
                    {
                        ItemsSource = items,
                        ItemStyle = BorderTop
                    },
                    new RadListView
                    {
                        ItemsSource = items,
                        ItemStyle = BorderTopAndBottom
                    },
                }
            };
        }
    }