Synthmaster One is a true wavetable synthesizer with wavescanning. You can also load your own waveforms and wavetables (you need an external program like Audioterm to create them)
2 independent ocillators (waveform or wavetable) with one sub-oscillator each (waveform only), 2 multi-mode filters in serial, parallel or split (each oscillator + sub has his own filter).
An effects rack, arpeggiator, 2 LFOs, 4 enveloppes, and an easy dag-and-drop modular modulation matrix. This synth is complete, very versatile and very good sounding.
Compared to Serum, the interface and ergonomy is less intuitive and clear (the waveform display is very small), but the sound is warmer. In my opinion, the Synthmaster One sound with the Serum interface will be the perfect wavetable synth .
The AcousticsampleS B5 is an ecellent sampling of a Hammond B3. In terms of pure sampling, it is miles above the Native Instruments one.
There's a lot of tuning options (individual drawbars volume, common hardware modifications, different amps cabs...). The Leslie emulation is not so good, but an update is coming with bugfixes, common controllers mappings and the new Rotary from UVI.
The sound is smooth, less "in-your-face" and brighter than VB3, so more suitable for jazz, pads...
It's a sample library, it works with the free UVI Player. The player is easy to use, stable and fast loading. It's protected by iLok, but no USB-dongle is needed.
And the developper is very kind. Watch his Wurlitzer library too...
Edit : well, the library have just been updated to v2, with 4 different Hammonds sampled (one B3, one A-100 and two C3), a new (and much better) Leslie emulation, bugfixes... I don't use VB3 anymore, B5 v2 covers all my needs. So I can change my rating to 10.