Define "Best"...
1. True cost of ownership over the life of the unit? My last Cypress 1 killed me with batteries and manditory 4 and 8 year check-ups.
2. Rumors of pre-mature firings on certain brands.
3. Maintenance issues/costs/batteries.
4. Real-life experiences with the various brands/customer support, etc.
5. Ultimately - reliability. Did one save your life or a friend's?