The trimetric 2030 has an adjustable low voltage alarm, a wide variety of adjustability, will auto re-set when the battery fully charges, and will interface with the SC2030 solar charger if you choose at a later time to go with a 30 amp or less solar system (60 amp option with two chargers and limited to 12 volt panels).
As for the smartgauge, or other voltage based devices, the debate on how to measure battery SOC has gone on for years. There is a lot to be said for voltage based calculation such as used by the smartgauge, but it has shortfalls, and can only tell you state of charge, not necessarily a meaningful "Remaining energy capacity" of the battery. Depending on battery condition XX percent could mean a lot of things.
Current flow based instrumentation does a great job of telling you what has gone into and come out of a battery, but again knowing that may or may not be useful in telling you how much useable energy you have in the battery, and if looking soley at current in/out you may not be getting an accurate idea of SOC.
Neither knowing voltage, or current in/out is ideal for determining when a battery is fully charged, so chargers, and some battery gauges use combinations of reading. The Trimetric 2030 for instance determines fully charged based on both battery voltage, and current flow at that voltage.
Voltage based system gives you an easily understood state of charge reading, but no real information as to how much current has gone into and come out of the battery. Current biased monitoring devices tell you about current in and out, and virtually always have a voltage function which is very useful in determining state of charge, especially since you can see battery voltage under specific load. You have to understand the relationship though and apply it to your battery setup, which for many isn't as quick and easy. Either system if utilized correctly should enable you to better maintain your batteries.
