SRAM/Rock Shox has the best CS in the industry, by far. That said, both Fox and RS make great products. I would consider Marz if looking for coil sprung stuff. We have warrantied far more RS stuff than Fox at my shop (over the last couple of years) but they are incredible to work with. Fox could definitely learn from RS in that area. Many people like the feel of the new RS stuff better, but that's highly subjective.
In my experience working on forks I feel like the internals in a fox fork are of higher quality, but the new RS forks are very light. Hard to choose. If reliability was my priority I would go Fox if weight and CS was my priority I would go RS. Fox makes it's internals available, they actually still offer parts for their first edition forks in the early 2000's (that can't be said for any other suspension company that I know of).
The lefty's not bad (it's retarded light and expensive in carbon) but they've quit making parts available for older models so I may be hard to keep the thing going for more than 5 years or so. Lefty's also seem to blow more often than other makes (we've replaced a ton of lefty Max seals). The newer models may be better though.