Yes, sumps offer more versatility for multi-stage filtration, particularly wet-dry filtration. However, they are definitely more work to set up and require more piecing-together than just unboxing a canister and getting it primed and running. Unless there's a very specific reason to have a sump setup, I'd usually recommend a good quality canister filter.
+1
On a 170 gallon, I'd even look at running twin canisters. The advantage with two canisters is double the filtration, the ability to alternate service and cleaning and subject your biofiltration to less impact that sometimes results from cleaning/service and if one filter breaks down or malfunctions, the other is still working.
Mark