Yes, my reason for the 0W40 was the fact that it is European spec and uses a much higher quality additive package than U.S. spec oils. Most of these oils cost $50-60 per change while this one is like $20-25 at Wal-Mart and I would have some leftover for the next change. I can purchase the Euro spec oils in 5W30 or 0W30 but they cost 3x the price of the 0W40. Mobil 1 only has one Euro spec oil and it comes in 0W40. It is a cost and quality of oil issue. As for the Geo, others on the forums swear by the use of the European spec oils in these tiny little engines. You don't want to use a cheap oil in these as they are very hard on oil. I have had no problems with lifters or anything else with using the 0W40 in this engine. Others also run the Rotella T6 0W40 which is usually lower cost than the M1. Basically, if M1 made a 0W30 or 5W30 meeting the Euro specs, I wouldn't think twice about using this over the 0W40. It is a cost and quality issue here.
I am all too familiar with the models made specially for Wal-Mart. I work on computers and see this all the time. Products such as this will have a special model number that will only be sold at Wal-Mart. Most of these I see are relatively low-end and low quality units. I wouldn't even touch the Black Friday specific models but that pretty much goes for these from ANY store, not just WM.
In the case of the oil, it is the same thing. Tires are a different story. I looked at tires from a chain tire shop and then Wal-Mart. The ones at the tire store were something like the Goodyear ATS while the ones at Wal-Mart were something like the Goodyear AT-S. Lets just say that these were Wal-Mart spec tires. Yes, they cost less but had a lower speed rating, lower tread life, lower traction rating, etc. I guess this kind of labeling is legal although still deceptive if you don't pay attention. A famous example of this is with Snapper Mower back in the past where they wouldn't agree to dilute their brand by selling a lower quality unit at certain stores and not others. You will find articles on this if you look it up. You will also find it seems that Snapper has a new CEO as they are selling at Wal-Mart.