The concept of "loving" or "hating" a tool is interesting. Both Jack and Brian have things to say about Microsoft Project. Jack as a user and Brian now as a supplier. But my take is from another view.
A tool is used to "get the job done." Can I use Microsoft Project to get the job done? Sure. How about Primavera? Sure. How about RTP? Sure. How about Excel. Yep I could.
But some tools are better at getting the job done than others. In the "good ole days" master plans were done with a special "planning board" that had tiny rows where you could stick colored plastic pins of different shapes. Connections between these pins was done with colored yarn. Then along came mainframes with a bed plotter connected. Well not actually connected, the plot job was queued to another computer (Gerber Scientific used minicomputers) that ran your plot job that was then rolled up and delivered to your "in box" down in the basement. Usually there was some kind a tear or ink smear so you were less than pleased with the output, let alone the actual planning content.
Big projects got scheduled this way though. They were done with with care and consideration because it took a day to turn around a plan. Did this prevent us from working? No. Did the project come in on time / on budget? Yes it did. Because the tool has little to do with the success of the project.
Any tool maker that claims her tool improves the project needs to provide some evidence this is so. This evidence of course is hard to come by. Even for the "big guys" like Microsoft. This why it turns into a tools religion discussion. "My tool is better than your tool."
So What's a PM to Do?
First of all don't succumb to the temptation to believe everything you read in the literature from the vendor. It is their job to sell you their product. That's what they're there for. Look around at working examples, not demos on the web. Ask people who have used the product. "Did this product actually improve the project in some measurable way?" If so "what were the units of measure for this improvement?" "Was there a baseline from which these measures were compared?" BTW if there was no baseline for measurement comparison, then hang up. This was no measurement.
Ask next "what's wrong with what I've got?" If it ain't broke don't fix it is the old axiom. This is especially true for tool. Sure there are lots of annoying things wrong with MSFT Project. But from my experience they are tolerable compared to other planning tools. Some tools don't allow you to assign more than one resource to a task. This means you have to have multiple the number of tasks by the number of resources. Some products don't have accounting calendars. This means you can't plan expenditures according to how your firm counts the money. This is bad.
Take the Broader View
Project Management tools are tools - they are not the solution to your project management problem. Find out how to solve the project management problem - then look for a tool to represent this solution.
