That depends on what you add on. Some templates can make it much easier to do. Some gear will open up SA options. Extra beatsticks in the party will keep you safe.
Is it worth it? Yes. When you can reach out and touch someone for the kind of damage a slightly optomized SAer can do then it is worth it. Crossbow sniper, Dark template, craven, and a few weapon crystals combine to make a very effective ranged sneak attacker with little investment. look for ways to get more attacks, and stay hidden. Also if you have extra resources, find a good way to punish anything that comes after you. Wand of grease or marbles. Poisoned caltrops. A BSF to hide behind. Things such as those.