The Deka Intimidator and its relabelled brethern are, in my opinion, a good starting battery for a car whose owner can't ever be bothered to check electrolyte levels, and has had terminal corrosion issues in the past they also could not be bothered with.
It makes an OK battery when cycled lightly and fully recharged promptly.
Perhaps the occassional deeper discharge. but the rest of their marketing.......No.
It cannot compare to a Lifeline AGM in total cycles accumulated in the same treatment, Unless of course both are chronically undercharged.
The best battery is not immune to chronic undercharging.
Manufacturer specs as to charging are general guidelines. Strict adherence is not totally necessary.
What is important is to reach as high a state of charge as possible before the next discharge begins, and to not overheat the battery.
Enter the manufacturer recommendations.
If exceedng manufacurer recommendtions were strictly prohibited, then the first pair of flooded golf cart batteries which received more than 32 amps would have exploded. Yet people here regularly charge them at 2x that rate.
If an 30% limited AGM is used as a starting battery, and say it needed a jumpstart, the alternator would easily double this 30% 'maximum' charge rate for a while anyway.
I am not saying that manufacturer recommendations are dismissable, I am saying they can be massaged.
6v AGMS do not enjoy the same advantage as flooded 6v have over their 12v counterparts, as flooded 6vs are true deep cycle, and 12v batteries, with very few exceptions, are not, and not even close.