A lot of the "hardware" synths have effects like reverb and chorus pre-applied to the voices.
They sound great out of the box.
Add a touch of effects to the soft sampler/rompler/synth and they wake up nicely.
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My Yamaha EX-5 sounds real good, but runs out of processing power quickly.
128 polyphony is good, but load a couple different voices and you get "DSP Full" messages.
I still use the EX-5 as a controller and also to add a FEW choice voices to the mix.
Any off loading of voices from the CPU just makes the whole perform better.
I consider hardware synths as a "poor mans UAD". Off loads the CPU work.
My favorite drum voices come off of a Yamaha TG-100. Don't laugh. It's 12 bit sampling at it's best.
After all, why are we Retro-ing into TR-808 synths? Why are there Lo-Fi VST effects?
Might as well use my Lo-Fi, retro, hard synths and off load voices.
Ultimately, it's the music that counts, and your ears that decide which tools to use.
I wonder if the Ipod kiddies earbuds can tell the difference between a hard and soft Korg?