Iwata users. opinion please!

it doesn't help that much unless you are using pretty much ink or acrylic thinned enough for washes.  my airpressure regulator on the compressor adjusts just well given my ability rite now.  the C+ has minor design changes from the older hp-C but that's it.  i do find the cup easier to wipe clean (by easier i mean comparing to the badger 100LG which has a similar cup to the older HP-C, if that justifies my comparison).  so all and all if you are happy with your hp-C, stay with it.  oh yea this is coming from a person who uses hp-CH and BH and am still using them.  i got the hi-line really cuz i wanted to try out the little gadget having the same curiosity as you did and it was only like 20 dollars more.