I assume you mean Deka (with a K). I install off grid solar systems for a living. I have installed hundreds batteries, both flooded and AGM, over the last 15 years. I've had very good results with them or I wouldn't keep using them. I typically see their AGM batteries lasting 7 to 10 years before needing replacement. I do think that Lifeline batteries are a little better but they are also more expensive. However, they make a wider variety of sizes so I often go with Lifeline if a different size works better for a given installation.
A quick googls search shows the Deka 8AGC2 selling online anywhere from $260 to $360 with most places about $300. What is CW charging?