I have been using Castrol ever since I started doing my own oil changes. Never read a bad review about them and its worked really well for me so far. I try and get the German made Castrol as its a much better grade than the North American made Castrol.
The German Castrol is readily available at most Auto Zone's. I have a German car and I have used that oil and also had it tested by Blackstone Labs and found it to perform well. It's a thick oil...closer to a 40 weight.
I've done Blackstone tests on a variety of oils from Castrol, to AMSoil, etc. My most recent oil analysis have been done at 10,000 mile oil change intervals. The best I've found so far is Pennzoil Ultra...the AMSoil is very close.
I have not tested the Mobile 1 for my Euro car because it has a history of shearing. I have used it in a 1998 corvette and have had success with that oil in a 5w30 weight.
At 3,750 mile intervals most any quality dino oil is fine. At the 7,000+ mile oil change intervals I would stick with a full synthetic. I'm probably going to use either Pennzoil Ultra or the AMSoil in my JX. I'm leasing this vehicle so I'm not going to obsess over oil like I do my other cars that I own. My 2010 Audi has almost 72,000 miles on it already. Every oil change analyzed. Fun hobby.
I do oil analysis via Blackstone on every oil change for my cars. I've experimented w/ lots of oils...M1, AMSoil, German Castrol, etc. My latest favorite oil is Pennzoil Ultra. It tests very close to AMSoil with slightly better TBN numbers on highly similar oil change intervals. My GTI loved running on the German Castrol...but it's closer to a 10w40 weight oil...might be a bit thick for the JX. I would go w/ either AMSoil or the Penn Ultra. Both are excellent premium oils.
I'll be using Amsoil Signature Series 100% Synthetic Motor Oil, Its there 25,000 oil I will most likely run it 15,000 and change the filter every 7,500. I have been using Amsoil in every thing I own for the past 20 years never had a problem.