I definitely prefer Guice. The only reason I'd put Rashaad over Guice is if he were more talented. But, Guice "slipped" as compared to dynasty pre-draft rankings not due to his talent.
You could argue Penny has a better opportunity, but that applies to both. In fact, last year, Washington's RBs gobbled up carries. When the backfield was healthy, they were getting 20 and more carries in various games. When Kelley and Thompson were on IR, Perine was getting 25+ touches.
Towards the end of the season, it wasn't just the RBs getting injured but throughout the oline. Hard to hold running inefficiency against the RBs, given that. A healthy oline blocking for a RB with greater big play ability will get more production from all those carries.