Use whatever weapon you want to when you merit: Hagun, Soboro, Tomoe. 4 hours meriting can get f*cking boring.
That said, if you choose to use a certain weapon, make sure you are doing the correct things to maximize it. Use the correct sub jobs for each weapon. Use the correct food for each, wear TP and WS gear that benefits each. Maintain a 6-hit [5-hit on pole.] Be aggressive on Gear swaps, WS, and use Overwhelm. Ride your abilities [Hasso, Medi, Zerk, warcry, jumps if available.]
These things will make you maximize your Sam more than using one weapon type at all times.
As for the question is Polearm good on SAM? For reference at colibri camp,
2187 Penta on my SAM/WAR, using mithkabob, minx2, no cor, no dia2, no angon
1946 Penta on my DRG/SAM, using mithkabob, min+march, no cor, no dia2, no angon
2534 Drakesbane on my DRG/WHM, no food, no brd, chaos+hunter's, no dia2, no angon