Most underrated VST synthesizer- just listen to the demo sounds at the rs-met site. One of the handful of software synths that does not need to be hyped with effects to keep up with real acoustic and analog sounds in the mix, or need these sounds to be watered down. But easily toned down to smooth padding if that is what you need because its strong presence is not due to harshness, but to clarity. Very expressive envelopes, smooth filters. Countless waveform possibilities. Far more sound design possibilities than first meet the eye- the envelopes and osc. parameters under "more" are key.
Great no-nonsense GUI. In fact, a no-nonsense synthesizer. The price is a mere token, if you are familiar with the prices of instruments with quality sound.
Only the lack of a true noise source keeps me from giving Straightliner a 10.
My first experience playing synthesizers in a public concert was with an Arp Odyssey- and it was not a "vintage" synth at that time. I still have hardware, including the original discrete analog Vermona monosynth and a Moog Theremin. Primarily I use Csound and acoustic instruments. Straightliner is the only VST synthesizer I still use, after trying and owning many, since VST first began.