RealGM

I've played in both but would like to know how do strategies differ between how you play each?

To win in roto you need a completely balanced team. Having players who hurt you in any category such as Dwight (FT%), SJax (FG%/TO's) etc, hurts you in roto and I personally try to avoid any players that hurt me in any specific category. You can't tank categories and expect to finish tops, hence Dwight Howard being a 2/3rd rounder in roto versus a consensus top 10 pick in H2H. The best team truly wins in roto but it can get boring if you're out of contention early. In H2H there are playoff systems where if you sneak in you can win. In H2H stats start over each week and you only need to win the majority of the categories to have a good team so strategy on how you put your team together is completely different.

would you treat injured players the same? For example, I hear it's good to grab Kevin Martin in Roto league's now becasue he'll make up for it, but in H2H, it's not good to grab him because you'll lose matchups for 6-8 weeks.

What's more important in regards to Martin is if you can afford to waste a roster spot for that long a period of time. For instance, in my roto league we only start 6 players and we have 82 game limits on each position so you don't play all your players. I have 6 bench spots that I will rarely ever play those players unless they are on a hot streak or an injury occurs. In that instance I would surely pick him up and he was never dropped in my league but I have a number of injured players (Love, Dunleavy) that i picked up thinking they could provide great value later in the season. If you're in a H2H league where you play anybody and everybody then you might think twice about it. Either way, I'd pick up Martin bc he is a fantasy stud, especially in roto bc he provides nearly the most helpful FT% in fantasy.

Bottom line: if you can afford to waste a roster spot without hurting your chances in the short term pick him up immediately, H2H or roto. He will probably provide better value late season in H2H bc it will be the equivalent to inserting a stud back into your lineup whereas in roto you'll miss out on most of his fantasy star power until he comes back in which most of the season will be over with.