Personally I don't like then they're to expensive for what they do and are almost always inferior to Sternguard. Vanguard with jump packs are ten points less than a same strength Sternguard squad and have one extra attack in close combat plus heroic intervention but that's meh, Sternguard get their special ammunition much better options much more versatility and benefit more from chapter tactics, if your playing competitively then Ultramarines tactics are usually best and Sternguard can deal with a load of other situations than vanguard while only being slightly worse in combat.
I run then with tigerius with divination which means that combined with his warlord trait they almost always reroll misses which when combined with poisoned rounds can deal with almost anything.
Originally Posted by Stella Cadente
The downside to a medium that allows the unlimited exchange of ideas, some people have some really stupid ideas.