So I had always being interested in the difference between different engine oils and after trying Castrol Edge 0w40 (US version, made in Belgium), Mobil 1 FS 0w40, and Shell Helix Ultra 5w40 (EU 1L bottles), here are some observations i found quite interesting. The car: 2007 E90 BMW 325i EU N52B25 KP 2.5 engine, has worn valve stem seals and may or may not have the inferior piston rings that burns more oil. Personal preference wise I have to admit I have had the worst impression with Mobil 1, in fact I have used both new FS formula and another Asian version that's a gold bottle, which i believe is the same content as the extended change version. Both Mobil 1 gets low quite quickly and i had to add 1L every 2000 or so KMs (even with Liqui Moly Engine oil saver). Engine feel and gas mileage was no different than Castrol. But Mobil 1 is the cheapest in my local shops. (A lot of you guys and some reputable mechanics in my area swears by Mobil 1, not doubting it's performance in other aspects but how are you guys doing oil consumption wise?) Castrol Edge had the best (lowest) oil consumption, new oil once lasted with 6000+ KM without loss (same Liqui Moly Engine Oil Saver added during oil change). No noticeable performance or gas mileage difference compared to Mobil 1. Recently put some Shell Helix Ultra 5w40 EU version in the car because it was on sale and I wanted some 1L bottles to keep in the trunk, then noticed a decent change in gas mileage (8.3L/100KM vs. 8.9 with Castrol, exact same stretch of 550km road with cruise control on most of the time), which is a nice surprise. Although if I remember correctly that's probably because it has a lower viscosity at 100C compared to the others, BUT, so far I haven't noticed any increase in oil consumption and it (with no additive) might even do better than Mobil 1 (with Liqui Moly) at least. Oh and all oils except the FS Mobil 1 were LL-01 certified (gold bottle Mobil 1 0w40 carries LL-01), although again i read somewhere it doesn't really matter much for NA engines? Anyhow, just some real life observations that i thought was interesting to share.