EQATEC is not totally free. It just offers a free licence (note: a limited one).
I've used ANTS performance profiler, dotTrace, EQATEC, Slimtune and among memory profilers Scitech and ANTS memory profiler. Memory profilers are a different kind of beast. I found Scitech the best one, although ANTS memory profiler also offers some nice results. Among performance other profilers, ANTS and dotTrace are superior to all other known to me. Slimtune is very basic, but ... it works. EQATEC was a mixed experience.
The problem with EQATEC was that it failed to start (no matter what I tried, a crash occurred) with one of the applications I worked on, but it worked with another one although the limitations of the free version were somehow annoying.
Profilers have a steep learning curve and it takes some time to get used to one, learn to use it the right way and interpret the results correctly. So you need to put value of your time, value of the performance improvement in your application and value of the profiler into the equation and decide then. I went for ANTS.
If you rarely use it, the free/limited alternatives may do just fine. But if it should be your productivity tool, go for one of the best ones, there are trial versions available.
You can find some very good opinions here: What Are Some Good .NET Profilers?
But regarding to your profiling requirements: just pick one of those, trial or free and profile that piece of code, giving money away for such a minor profiling task is rediculous.