Alpha cards hold up in value and can appreciate down the road. However at higher levels it will be difficult to raise in leveling. The ROI for using alpha, 10% more DEC, does not seem sufficient compensation compared to beta and the upfront cost to go with alpha can be more than twice of beta.
If you play a lot I think beta is the way to go, that way rise higher ranking and every win in the higher ranks earns more DEC. If you are a collector go with alpha as it will likely to continue appreciating.