Anthony - it is a good brush, in fact for a long time my main brush. It does ok with finer lines but not as fine as a gravity fed can do. If you are on a budget the Omni 4000 can get better lines than the 155 for about the same price. The Iwata HP-CR can get some very fine lines as well (I own one of those now and it is my main brush) and it runs about $70, the same as the Omni.
What type of models do you normally paint? If it is 1/48 Aircraft and 1/35 tanks then the two I recommended would work great unless you are really into German squiggle camo or something intricate like that.
*edit* - didn't want to downplay the 155 totally.. it is a great brush... if you have an opportunity to get one cheap it will serve you well. But if you are buying new, the other two would do better for you I would think.