the best thing about TCAS is that it shows you which direction to look.....without an azimuth display I wouldn't waste my money.
Within reason, since the azimuth accuracy can be up to 30 degrees out. You may end up looking to the left of the nose when in fact the traffic shown on the TCAS is actually off to the right.
TCAS systems in use (TCAS I and II) do not provide horizontal avoidance advice. TCAS III intended to use the TCAS directional antenna to provide horizontal avoidance but was abandoned by industry as not being good enough for the job due to the bearing inaccuracy mentioned above.
TCAS IV should improve this accuracy by including positional information sent from the target aircraft (encoded from GPS or similar onboard source) and so will also offer horizontal avoidance advice.