Yvon, your English is just fine.
A good converter like the Inteli-power over its life span will pay for itself by keeping a
battery properly conditioned and protected. A good converter is equally or more important to the longevity of a
battery, then the type of
battery itself. Yes, even for the Walmart batteries.
The Delco Voyager and Optima are both good batteries, and perform well. The Optima is rated for about 1/3 more charge cycles, but cost twice as much.
One other reason for going with a better deep cycle battery, is that they can often take more then twice as many charge cycles.
I know I'm going to get more bashing from the Walmart fans, but the OP did ask for opinions after all.