Clockwork Mod. To flash or not to flash?
This is entirely up to you, and your personal preference.

There is one thing I would suggest though: do not use ROM Manager! It has a nasty history of damaged devices.

I would suggest that you go with either CWM or TWRP, if it is available for your device. I would suggest you flash it using fastboot, if it is available on your device.

If it isn't, then you should see forums such as xda-developers for info on how to flash recovery images.