This is a good synth. If you are just comparing raw capabilities, it has a basic sound and features roughly comparable to synth1, but monophonic. So if you were gonna start all your patch programming efforts from scratch, you should probably just get synth1 and concentrate on that. However, if you like to have lots of presets to listen to for song inspiration or just starting points to create new sounds, then you have to get Triangle II to mine the huge number of banks that are available here at KVR and other sites.
The basic sound of Triangle II is generic in a good way. It doesn't jump out at you the way that a Crystal or a Protoplasm does. It's 'in a good way` because you need those bread and butter sounds to round out your sonic creations.
Watch out when you hold down keys as you change presets, you will often be greeted by strange sounds that don't seem to come from the preset you started from or the one you ended up at.
Like synth1, CPU usage is tiny. Probably as little as any VST instrument.
For their other freeware (Square I) it is the same punishment: too old for the taste of Gibson (the new owner of Cakewalk), so it went to the dustbin as well. But the problem is that the download file for "Square I" has never been kept by the history (the Wayback Machine). And it is not available at Pluginboutique either. Conclusion: this one is lost for the eternity...