Depends on bomb size. The thing is the 217 could carry some larger bombs internally, where the 188's internal bays were limited to only 50kg sized bombs or aux fuel tanks.
So up to a certain point the 217 would be faster at max speeds, but have worse range and much worse handling (and a lower ceiling). However, a number of loadouts on the 217 required the external ETC racks between the fuselage and the engines, which would have slowed it down as well. So, for Aces High's use the 217 would be better if "clean" externally, since most people run full throttle all the time anyways. Even though it was fast, it was considered woefully underpowered for the loads on the wings and not very responsive in handling or performance. Later models tried to remedy this with longer wings, but it didn't help all that much and in the end the engines were needed elsewhere and the production was cancelled in favor of He177s and Ju188s.
That's only for conventional bomb use, though. It almost seems more were used in combination with the Fritz-X and the Hs293 than were used as conventional bombers. These required external loads and slowed the plane down more, and when these loads were used the internal bays were required to load fuel tanks.
P.S. The 188 reportedly climbed much better than the 217.
P.P.S Karnak: While I believe the 188 had better defensive guns, but the 217 could also have a fixed forward 20mm. Problem is according to its handling and performance you'd almost never get it on target in Aces High and it would be only good against ground targets or HO defense.
