Solar powered bird baths

Hi all - I've asked this question under ask an expert but probably that was the wrong thread, so here I go:

We've had a standard RSPB bird bath in the garden but it's not getting much use (some birds do use it but nothing spectacular). Having seen Yas's videos from her bird bath we decided to get a solar powered bird bath with running water as the sound of the water running may encourage our garden visitors to use the facility. 

I've had a look here: http://www.britishbirdlovers.co.uk/bird-baths/buy-solar-powered-bird-baths  and seen a variety of types and models but I am not sure what to get so your advice will be very welcomed, particularly in the following issues:

1. Size / depth of basin for optimal use by the birdies,

2. Number of jets (if that is of importance),

3. Heating necessary? Is that separate or some models/makes come with it?

4. Is the height of the stand important, if so how tall should it be?

5. Anybody is using one and can recommend?

And finally, important questions I forgot to ask?

Thanks in anticipation of your replies and advice!