In all honesty, any oil from a reputable manufacturer that meets the spec is going to be OK. The only engine failures I've seen where oil may have been an issue have been where someone put totally the specification in because they thought they knew better or they used the cheapest oil that money could buy.
If anything I'd go for an oil that costs less and change it more often, I've seen the GM 5w30 for sale at £20 for 5l when the top end mobil 1 is nearly £40, personally in this situation I'd go for the GM stuff and replace the oil more often but would always use a genuine Saab oil filter.
I've never seen a car suffer from problems caused by using the GM oil, on top of that I've seen a car where the owner had only used mobil 1 (and changed it every 6k) and they had a blocked strainer and needed a sump drop but this was caused by the breather kit and wasn't a problem with the oil.