I went with AMSOIL mainly because I can't find anyone that shows the results of similar tests. And they test against the name brands. I've posted all my thoughts here:

http://forum.ls1truck.com/index.php?showtopic=7983&st=0

 

I don't think I'd say they're all equal. There are tests that show some break down a LOT faster than others, some don't cling to parts well resulting in scarred engine parts due to metal on metal, etc. Not trying to be argumentative, but there are pretty conclusive tests showing good and bad points of some of the oils out there.

 

Not to argue-just my own exp with Amsoil and I have customers who swear by it.
I had a bad issue with Amsoil 10-40 with their filter on a new motor.
I did filter swap at rec 7500k and topped off as per Amsoil.
At 11000 miles eng failed.
Engine dropped valve due to broken valve retainer but sent oil sample to Amsoil,Castrol and a indy lab anyway.
Both Indy and Castrol said oil was "clumped" due to improper blending of inert elements of the oil additives.They also said oil was on the verge of the vis of a stright 50wt.
Amsoil never replied even though I was a stocking Amsoil dealer.
Also had a issue with a 770r4 trans and od hunting with Amsoil(cust supplied Amsoil)-changed back to Dextron problem gone. Customer couldn't beleve it also(he is a Amsoil only guy)

Swapped to Royal Purple since with out any issues.( and also trying Klotz in my truck now).
The Amsoil site doen't test Royal ,Torco, Redline, Klotz or I missed it.
http://www.bestsynthetic.com/comptest.shtml

Not saying Amsoil is bad-just some of the few things I had happen to me over the years .

I stand corrected they do a comp test on red line and rp but with 20-50 racing oil which we don't use in our trucks.

Use what you feel is best no oil will keep it from blowing up under over extreme measures and change it at 3 -5 k max.

 

I just use mobil one and forget about it. You dont need more, even if the others are actually better.
Its been tried and true to 200k+ miles. I'm not at all worried about spinning a bearing or wearing rings before that.

 

I've had good luck with Mobil1 fully synthetic...it's a little more expensive than the dino oils, but cheaper than Amsoil and Royal Purple (which I don't have personal experience with). If you keep your eyes open, you can find Mobil1 on sale at either WalMart or Kmart pretty often.

 

if you've run regular oil for any extended period of time, switching to a cleaner synthetic will take several changes to flush all the "impurities" out of the motor. i''ve run mobil 1 for the past 6 changes.

 

castrol syntec in my truck, royal purple in the buggy . haven't really noticed any "advantages" thus far with the buggy. Personally I can't see any reason why I should switch from the regulare ole stocky pennzoil **** to synthetic... only reason I went castrol syntec was the rebate from oreillys lol


oh and i forgot to add, if you're inquiring about oil filters (i forgot what the post was referencing in its entirety due to my miller juice) I always use fram because of the nice design, it looks purrrrrdy