No, there's not really any difference in brands as long as you stay with a name brand. Write down the specs listed in the manual for the oil. I.e., not only the weight but the service classification (such as "SF, SG, SH, SJ or higher"), and buy a name brand oil that meets those specs, and you'll be good. Then at 50 hours or 100 hours, I'd recommend changing to a synthetic oil that meets the specs in your manual. But that's just a personal thing with me. So long as you use a good brand of oil (whether dino or synthetic) that meets the specs in your manual, you'll be fine.
And when you replace the oil drain plug, don't go all gorilla on it. Some people have been ham-fisted and stripped the threads by over tightening. You want it snug, but not too much. If you have a torque wrench, tighten it to the torque specs in your owners manual. Same thing with the oil filter. You want to spin it on by hand and tighten it hand tight, and maybe another quarter of a turn with a filter wrench. But you don't want to tighten it too much. Just follow the manual.
