PowerControl is still the best. No need for a nifty, but unreliable, high maintenance GPS/ANT+ device. Instead, turn on the Strava App on your phone, place it in your back pocket and go for a ride.
To have Strava display the power data, the datasets recorded by your Strava Phone App and your PowerControl need to be synchronized. This is exactly the kind of kung-fu SRM2Strava does. It is done in 3 steps:
1) Get the SRM & GPS files.
Use the export features in SRMWin to save your data as "Training as text file(new format)". For the GPS data, you can use the "export GPX" feature of Strava in the Actions menu.
2) Load both the SRM and GPS files into SRM2Strava.
SRM2Strava computes the riding speed from the GPS coordinates & automatically synchronizes it to the speed data recorded by your PowerControl.
Sometimes, on the first pass, the fit is not satisfactory. This usually happens when one device started recording much later that day--think time it took to get rolling out of the parking lot or garage. In that case, use the "Crop" feature and see if the synchronization improves. The plots will be adjusted on-the-fly with each move of the sliders. Note, this "Crop" feature does not delete data points, it only shifts the data-window to consider for synchronization.
3) Download the TCX file
Once you deem the synchronization satisfactory, click on the "Download TCX" button. This will provide you with a file that Strava can handle with the GPS coordinates & with the synchronized power/heartrate data. You can then upload it to your Strava account & replace the existing entry your Phone App created. Note, Strava checks for duplicate entries therefore deleting the original entry is necessary (don't worry, if anything bad happened with SRM2Strava you can always upload the original GPS file back to Strava).