I owned the A3 for a while to blend a mic & piezo I found it a little brittle sounding, the effects are not as good as the B1X series. It was passed on to me by my guitarist who bought a baggs system. I sold the A3 and pickup a Radial Bassbone OD which I used for blending a mic & piezo though I did need an Impedance booster for the mic. It sounded better than the A3.
I have since bought the Zoom B1Xon and sold the Radial Bassbone as blending a mic and piezo is not critical for me. Now I use an fDECK preamp into my AMP and use a clip-on mic straight to the mixer, where both signals can be blended.
Apologies for the long-winded answer but as you can see I've been down this rabbit hole for a while. Your needs may be different to mine but just sonically speaking, if you have a good amp you only need a basic preamp (Fdeck) as far as fx go, the B1X beats the A3.
I get a great tone from my fingers and a well-placed mic with minimal eq needed, the piezo is used to add a little bottom end thump, most of my tone comes from the mic.
Hope this helps