Older bass player here. When I was younger, I could play either without noticing any difference. Now, I have a Squier Jag SS, which is contoured and a Mustang PJ SS which is slab. I find the Squier much more comfortable than the Mustang. Although I have tried different strap lengths and body positions I cannot seem to find a comfort level with the Mustang. Am I missing something or is this a common thing that relates to personal preference? Any thoughts would be appreciated.