The Pivot Mach 5.5 may be one of (if not THE) most capable trail bike on the market today. The DW link suspension has unparalleled pedaling efficiency given the 140mm of rear travel, and the extra oil volume with the piggyback dpx2 shock makes the bike eat up long rides on aggressive terrain. The super boost spacing is offputting to some, but the frame's stiffness is world-class, meaning that the bike is crisp, efficient and super predictable.
When running this bike with the dpx2, it may be challenging to fit a full size water bottle in the frame in sizes S and M. My large frame fits a bottle no problem, and with the addition of the OneUP EDC tool, I can get away with riding without a pack most days. Whether riding gnarly trails in Moab or long singletrack epics in Park City, the Fox 36 up front will keep things under control while the DW link out back keeps you pedaling comfortably for hours. No bike is perfect, but with some tweaking, I really believe this rig could function effectively all the way from lightweight trail bike to a bike park ripper. If you're interested in this bike I'd suggest demoing a rig to dial in sizing. Once you've tried it out, it may be tough to walk away without one!