The foot dome is one of the main reasons we decided on the Sundance Optima (awaiting delivery in next week or so!). In addition to a continuous foot masage massage
it provides a convenient foot rest to help keep you seated when the jets are full blast. The no-foot-dome camp says that foot domes are awkward and easy to trip over, but personally I've not experienced that. (Typically we slide from seat to seat rather than standing and walking across the tub).
All that said, you won't know what's right for you until you try a few different models and see what works for you.