Samplers ROM Players and samples in general, are a bit different, the quality of the original sample is essential to a good result, and this can be continued within the library.
At the end of the day, it's a complete package that I look for in a synth or sampler, that means workflow is going to be easier and the onboard filters and effects are strong enough to remain consistently present in my sets without worry of saving a patch with them in.
All bells and whistles isn't really that helpful, I've certainly moved over to the 'Only buying version changes' no new synths as I have one or two from the main types of synth & hybrid samplers.
Wavetable synth's are my favourite for all over sounds and patch design such as Pads and interesting electronic morphing soundscapes.
Subtractive are my favourite for Plucks, Arps, Leads.
FM or (FM8) is best for unusual Base, Pads and FX.
Samplers tend towards, Pad's Drones Soundscapes FX and good one shot drums etc.
In a nut,
