SANS  2.1.8 seems fixed problems I was having (see below). Otherwise, did not see any other resource monitoring tool on Mac, even remotely close to iPulse by UI/Usability/Information per screen real estate/Price ratio! Well deserved 5 stars in each category!  
(Version 2.1.8)

JAMESKITTY  i hate "conceptual" interfaces. i spent ten minutes trying to figure out where i was supposed to click to get the information i was looking for. even loaded each of the alternate designs included.... still couldn't do it. nor could i figure out what the menubar was supposed to be indicative of.

went straight in to the trash.  
(Version 2.1.6)

NCIANCA  The latest version (2.10) of iPulse has a huge problem.

"You are now prompted for a password each time you launch iPulse on Snow Leopard"

Why can't it remember the setting? Why do I need to enter a password every time I start iPulse? Apple's "Activity Monitor" does not prompt the user for a password every time it is started.

If it can't be fixed because there are inherent problems with the way that iPulse is implemented, then that security vulnerability should be addressed and fixed rather then creating a huge inconvenience for the users.

This change means that I can no longer have iPulse as a startup item has I have for years.   
(Version 2.1.10)

CERNIUK  A re-ranking. First and foremost the system lockup problem: If you run iPulse on a laptop and use iDisk or other servers, you will find that iPulse will habitually lock your Mac forcing you to control-command-power hard reboot to get free.

iPulse will check the mounted volumes (hard drives) including remote server volumes periodically to update the usage status. When it does this and the volume is no longer available, it will not time out nor release the query call for disk usage statistics.

Here is the scenario: You are at work and you have a server mounted. Maybe it is your Windows NT corp server, Mac OS X corp server, your iDisk cloud server, or your TimeCapsule volume. You close the lid to sleep the Mac and it sleeps. Pack it in your bag, jet for the door. You then later open your Mac (on the train, at home, etc.) and you have no network connection or a different network connection that does not allow you to get to one of the servers that you were connected to before. iPulse will go brute force against that server asking for statistics and not let go. That server volume appears busy and the Finder cannot let go either. You establish an Internet connection (wifi, ethernet, cell modem, etc) and now nothing seems to be able to talk to the network even though you do have a connection as verified by the Network Preferences in your System Preferences. Then you check your process list (command-option-escape) and note that iPulse is not responding. You figure, ok, just kill it but that thing is a vampire and drains your network connection dry and cannot be killed. Kill Kill Kill, nope nope nope. Then you see your Finder go non-responsive. Kill, nope. Other processes, as they access network resources start to go red including iChat, Pages (oops, update check...) and others. Some kill, some do not. You try launching network utilities that just seem to bounce indefinitely (they are trying to open network connections and the network stack is gridlocked by iPulse, sorry charlie)

Ok, long story short, your Mac is Tango Uniform, time for the three key salute: command-control-power. This time you take iPulse **out** of your login items and come and write a lengthy review about one of your favorite little utilities becoming more pain that it is worth. Sad Monday, lost an old friend.  
(Version 2.1.9)

AV  Brilliant. Ive used it for years now and its the first thing that gets installed on any Mac i use and sits on-top on all windows in the bottom right-hand corner (transparent background and nice subtle coloured indicators). It tells me at-a-glance what the Mac is doing internally - its indispensable. You can see very quickly if an app glitches in the background and the processor is sapping battery power, or if data is being downloaded or uploaded, hard drive is being read, wifi strength, battery indicator etc etc etc - all instantly & beautifully- AND it tells me the time, moon phase and not to forget the info panels! Absolutely Perfect. And the price is also well judged (for me!). Please continue to develop this superb application.  
(Version 2.1.9)

LEE123  Yes, it takes a few minutes to learn the interface but once you do this app is great. It tells you everything activity monitor or x resource graph does but in less space and it is infinitely more customizable. I have been running this for 4 months and it has never crashed or caused me problems. You can also access activity monitor, terminal and network utility with just a right click. Also, instant access to processes, memory and network activity. What a great tool.  
(Version 2.1.8)

SANS  2.1.7 has problems displaying network speeds on my MacBook Pro - negative speeds, ridiculously large speeds, etc. 2.1.6 seems OK.  
(Version 2.1.7)

SLOB  Are the previous reviewers using iPulse itself to read CPU load? In which case, yes, it reads 15 to 20% (omm, a p'book with Tiger), but check Activity monitor and it's only using around 2%.  
(Version 2.1.5)

AMBERV  Maintenance for this product has slipped woefully in the past year. They built the features up to a really great set, but then decided to let a few really major bugs slide -- seemingly for good. It has been many, many months where this app just doesn't work that well with Tiger. They seem to be doing very little to rectify this situation. Look at the latest update -- fixing a graphic in the help file (?!) That's the kind of dumb stuff that doesn't even get mentioned in a Real update. Here, it is a major feature!  
(Version 2.1.5)

ANONYMOUS  I think iPulse is great but every version I've tried since 2.0.2 on Tiger has given me enourmous trouble after an hour of letting the app run. There seems to be a memory leak that is allowing iPulse to consume up to 95% of my iBook's resources. Please get this issue fixed, because the newest features are quite nice except for the fact that they become unusable if the app eats up so much CPU power.  
(Version 2.1.3)