Custom cell in table using grid via XAML?

I have a form with a custom viewCell that looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="EvalUate.DetailsPage" Title="{Binding Name}">
    <ContentPage.Content>
        <ScrollView>
            <ListView x:Name="CriteriaList" ItemsSource="{Binding Criteria}">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <ViewCell.View>
                                <StackLayout Orientation="Horizontal">
                                        <Label Text="{Binding Name}" />
                                        <Label Text=" " />
                                        <Label Text="Rated: " />
                                        <Label Text="{Binding Rating}" />
                                        <Label Text=" " />
                                        <Label Text="Value: " />
                                        <Label Text="{Binding Importance}" />
                                    </StackLayout>
                            </ViewCell.View>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
        </ScrollView>
    </ContentPage.Content>
</ContentPage>

the problem is that the columns do not align. I thought I could replace the StackLayout with a Grid, but I can't seem to get that to work. Here is what I tried,

<Grid>
    <RowDefinitionCollection>
        <RowDefinition />
    </RowDefinitionCollection>
    <ColumnDefinitionCollection>
        <ColumnDefinition />
        <ColumnDefinition />
        <ColumnDefinition />
    </ColumnDefinitionCollection>
    <Label Text="{Binding Name}" Grid.Row="0" Grid.Column="0" />
    <StackLayout Orientation="Horizontal" Grid.Row="0" Grid.Column="1">
        <Label Text="Rated: "/>
        <Label Text="{Binding Rating}"/>                                        
    </StackLayout>
    <StackLayout Orientation="Horizontal" Grid.Row="0" Grid.Column="2">
        <Label Text="Value: "/>
        <Label Text="{Binding Importance}"/>                                        
    </StackLayout>
</Grid>

But this throws an exception. Is there documentation on using a grid in XAML?