I checked out Iota when I was designing Beausoleil's electrical system. They're well built, inexpensive, and are capable of bulk/absorption/float mode with an optional smart regulator (which can be ordered pre-installed). Stack a few in parallel and you can charge just about any battery bank. Good buy for the money.
However, there was one drawback that was a killer for me. There is no mechanism for sensing battery temperature - which is mandatory if you want to charge a battery bank in as little time as practical (blast the batteries at the highest rate they can absorb without gassing). For me to keep genset running times to a minimum while on the hook, it was a deal breaker. The other problem for me is that they aren't available in a universal AC version (120-240V/50-60Hz) for international cruising.
For someone who spends most of their time in a slip, the Iota's are a good bang for the buck.
1979 Formosa 51 Ketch
Homeport: Marblehead, MA USA