My two cents.

Consumer Union have, from time to time, made impartial tests of the most popular brands of motor oil and have invariably reported no noticeable difference in performance. I think that the perceived better performance of one brand over another is a great example of the art of merchandizing.

I use synthetic meeting the SAE specs for my car and I don't really pay attention to the color of the containers or the name written on it. I am absolutely convinced that if my engine fails it won't be due to the quality of the oil.

I use 10W30 in the winter and 5W50 in the summer. If your winters are not cold, which I don't think they are, 20W50 seems a reasonable choice. Synthetic is better than regular because it is more stable at high temperature and therefore does not degrade as quickly.

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Reno

'93 300E 4Matic
'98 Nissan Altima
'00 Yamaha Road Star Silverado