It's not the brand that makes the difference - lead-acid batteries are a mature technology and pretty much a commodity. You can get a longer life by selecting a variant more suitable to RV use (deep cycling) and by providing good maintenance (or using a sealed, maintenance free type).
At a guess, your Excide was a 12v hybrid called the marine/RV type. Even with care, they rarely last more than about 3 years in typical RV use. A true deep cycle flooded cell battery such as the golf car 6v's or a Trojan 24TMX will last 6-10 ears with modest care. An AGM 12v deep cycle will last 6-8 years with no care at all. AGMs cost substantially more, though.
Please read my short article on RV battery choices. It's in the RVForum Library at http://www.rvforum.net/miscfiles/Choosing_right_battery.pdf