I have to be honest. Space Marine Bikes, particularly White Scar Bikers, are probably the best army style available from the Space Marine Codex. Combining Hit and Run, Skilled Rider, and often Scout, this army is fast, durable, and reasonably hard hitting. This has led many Blood Angels players to take bikes as well, expecting them to be just as useful.
Do you know what’s a very poor trade for Hit and Run, Skilled Rider, and Scout? Furious Charge. We pay the same points for our Bikes as White Scars do, but ours are far less mobile or durable. Our bikes are still a good platform for grav weapons (the best in our army), but I honestly haven’t been that impressed with grav. Oh, it’s amazing on Devasator Centurions or Biker Command squads, which can put out a large number of shots, but Bike squads can’t really reach those numbers. If they take heavy fire, they’ve got to Jink (which is not as good as a White Scar Jink), rendering the grav guns almost completely ineffective.
I’m not saying that grav Bikers are a bad squad. They have their place, but if you fill up your Fast Attack slots with them, you will likely be disappointed. Grav guns have great hitting power against high toughness targets with a great armor save. They only work for other targets when you can produce a large number of shots, either through lots of Bike squads, grav cannons, or Command squads that can take 5 grav guns. Blood Angels don’t have any of those options, so we’re best leaving massed grav to Codex Marines. One squad with two grav guns and a combi-grav is a great addition for hunting monstrous creatures, but don’t go overboard.
I think our Assault squads are a better option for delivering meltaguns.