I have been playing acoustic guitar for 45 years as professional in clubs. As such I have been through almost every system that has been available since that time, always searching for "the acoustic sound of the guitar". In the 1970's I started with the Barcus Berry hot dots and up to the Fishman Blender System, and everything else in between.
The L. R. Baggs Anthem system is the latest in the search and, in my opinion, the best yet.
One nice thing about the Anthem is that, apart from the hole for the end pin jack, no cutting is necessary for preamps in the sides of the guitar. The preamp fits perfectly inside the sound hole with access to the controls at the upper edge of the sound hole.
The controls:
Master volume, a phase switch, which is a great option, a blend switch which can give you the condenser mic alone or a personal mix with the under saddle pickup. The under-saddle pickup takes care of the bottom end lower frequencies, which I believe has a crossover at 250Hz. There is a battery test button where there are 5 green lights that show how much life is left in the battery. Finally there is a trim control for the adjusting the optimal mic volume for the particular guitar. All of the above functions give meaning and all work to satisfaction. I have had no problems at all.
The Anthem is definitely a great system and by far the best acoustic system that I have tried. There is great depth in the sound where you have the clear sound of the condenser mic, which I sometimes use for direct recording, and the mix with the under-saddle for live playing inhibiting mic feedback and insuring proper volume and bottom end.
While the optimal onboard system has not been built yet the L. R. Baggs Anthem for acoustic guitar will definitely be the one to beat for those involved in creating optimal acoustic guitar amplification in the future.