I would definitely go with Vikavolt here over Orbeetle. As Brute force is far better for in-game strategies, Vikavolt's 145 Special Attack far outclassed Orbeetle's 80. Additionally, with the introduction of TR's in Gen. 8, Vikavolt has a great new in-game movepool it would normally not have access to until far later in-game. These include Thunderbolt, Bug Buzz, Air Slash, Energy Ball and Flash Cannon which is good coverage. While Orbeetle has decent coverage in Psychic, Shadow Ball, Bug Buzz, and Energy Ball, Vikavolt has better. Vikavolt's STABs cover Milo, Nessa, Piers and Leon's Charizard. It has coverage against Opal and Melony as well.
Hope this helps!