Janice, mostly depends if you plan on changing things. The core rifles are the same. I've personally never been to fond of b5 furniture, so just your preference. If you want to experiment with different stocks, pistol grips and stuff I'd just grab the standard model. If you plan on keeping the rifle as is the b5 will be a slight upgrade in comfortability vs the standard. If this is your first AR I'd just grab the standard because you will likely upgrade parts anyways. Hope this helps.

whichever you like the most. they will both do the job

Hi Janice and welcome. I would go with the B5 Furniture Model over the standard model. Cheers and stay safe!