We use to travel to SXM in both April and October and the difference is the weather and amount of visitors. We have found it more humid with more rain although I believe we only had two wash out days in those 8 late October visits and another one or two in early October.

We use to travel the second week in October and there were still a few restaurants closings but by the third week they are all open. I can't say I've noticed a significant difference in crowds in April and late October. Maybe the week of Easter was crowded otherwise we got around easily and no issues with more people in April than October.