ZEROLIGHT  @Castle. You can limit CPU usage. Preferences, Par2, CPU Usage - default is 2 cores. I have mine set to 1. Frees up the other core for other tasks.  
(Version 3.8)

CASTLE  Great app - I really couldn't live without it. I do wish the CPU usage could be limited, though. On my MBP running MacPAR will make playing any kind of video impossible.  
(Version 3.8)

LENNY81  I don't see in the preferences, any option for overwriting files instead of renaming them. something which quickpar does and saves unnecessary time wasting. (Deleting old parts after being renamed then running the application again to correct the renamed files.) All broken part get renamed to xxx10.1 xxx11.1 etc.  
(Version 3.8)

SMOLDERSONLINE  Fully agree with serphium's review - an excellent tool. Indeed an option to turn off MacPar searching for files would even enhance the tool. Thank you!   
(Version 3.8)

MAGENTIS  Overall, an excellent program. Does what it's supposed to do.

I do have a few wishes though.

MacPar likes to look at all files in a directory (even if they are not matched by name in the par file). It would be nice to have an option for turning this off.

A built-in SFV checker would be wonderful.

And this is just a little nitpick, but the icons look quite dated. Would be nice to see them refreshed.  
(Version 3.7)

DOM21  Indispensible. Five stars. For the _rare_ times this won't do the job there are other apps that will.  
(Version 3.7)

ALJUK  A very useful tool. Works perfectly.  
(Version 3.7)

AQUAX  Phenomenal. Very Mac-like in the UI, but handles Windows created PAR, RAR, etc, with no sweat.  
(Version 3.6)

WINGS  What I've always wanted in an app like this is the ability to UNrar a set when there is 1 or more missing pieces (and none or not enough PARs). Not useful for getting apps from the newsgroups, but at least for music or movie files, you'll get SOMEthing rather than nothing.  
(Version 3.6)

JAZZADDICT  Sweet! Works without a glitch. What would I do without this .app? Worthy of a donation for sure!  
(Version 3.5)

ANONYMOUS  this software rocks , much better than stuffit   
(Version 3.2)

ANONYMOUS  a genious software, much better than stuffit to decompress .rar archives.

this piece will rock !   
(Version 3.2)

ANONYMOUS  Very nice par utility. One wish list item though - having to rescan the entire volume set when attempting to recover after obtaining additional needed .par2 files is painful. Hopefully future versions won't require this.  
(Version 3.2)

PJM  MacPar Deluxe is probably the best rar/par archiving and expansion product available on the Mac. Other options such as Gumby and UnRAR X do not have the same ease of use. Simply associate all par and rar files with MacParDeluxe and double-click. Easy as pie.r01 and pie.r02 Its integration with Split & Concat has made it an indispensible tool in my Usenet surfing toolbox.  
(Version 3.1)

BLUEBELL  An excellent piece of software that does exactly what it says, without any fuss or bother. I've not had any problems with it, running on OSX 10.3.5  
(Version 2.6)

INDICES  This is a very excellent utility for both .par's and .rar files... does a great job with Usenet binaries! Thanks for this valuable addition to the OS X kit... and thanks for your generous shareware terms!  
(Version 2.6)