welcome to vassal...
or try proxying, read up on their rules, find some army lists, then try them out.
maybe you won't like a marine company that might run away every time they lose a man. usually charges the nearest enemy, and has no stationary firebase
or maybe you won't like marines that are always more expensive than their regular codex counterparts, but get a few bonuses.
do you want bikers with scout, fearless, teleport homers, and a troops terminator unit that deepstrikes first turn, and is fearless, and great at both ranged and cc. all the while costing an average of 50 points per kick ass marine
or do you want an entire army that rerolls to hit with their 2 attacks, and has cheap ablative wounds in their huge quasi fearless squads, plus has great reasonable hq's and the old cheesy style of 3 point traits, 2 low point assault cannons per terminator squad.
i think stylistically that black templars is as horde as a space marine army gets, while deathwing is as surviveable/maneuverable as a space marine army gets.
by the way, i have to say that even if you don't want a named character belial is a bargain that might just force you into using a counts as to get his rules, and stats but not be the master of the deathwing himself leading the charge.
good luck, try before you buy