Are you running synthetic fluids now? Do you have any intention on running extended drain intervals?
If you do not plan on running an extended drain interval, say over 5k, with either syn or dino oil I personally think bypass filters are a wate of money.
Look at some of the low mileage oil analysis? There is very, very little wear with short oil change intervals.
If you are planning on extending the drain interval then the benefits of a bypass filter are more prevlant, IMHO.
With that said, I agree the Oilguard seems to be a better unit that the Frantz.
If you do a lot of extended driving, the Spinner is a pretty slick bypass filter. The problem is it only works best when oil is up to operating temp for extended periods of time. If you do alot of short in town driving it is probably not the best alternative.