Risen is most enjoyable during the first two chapters (there four chapters in total, not six as in the Gothic series, but the game feels about the same length and the chapters are divided more evenly this way). After that there are far fewer quests available, much like the first Gothic (as opposed to Gothic II, which has new side quests in every chapter, especially with Night of the Raven). Overall it's a very enjoyable experience, however, with some great character development, "power struggle" quests that make tangible changes in the main town depending on your choices, and clever dungeon puzzles (the dungeon puzzles are a bit like Night of the Raven's, except spread throughout the whole game). As you rise up the ranks of your faction there are additional benefits and quest opportunities beyond just getting fancier armour, and members of your faction will respond appropriately according to your rank.
Arcania is going to be substantially different from Gothic, unfortunately. Among other things game areas are locked out when moving to a new chapter (rather than being recycled) and skills are trained through a skill tree system rather than trainers. The game is still in development so some of this may change, but it's still going to be vastly different.
Namur: As for Lares, if you give him the list you'll be betraying the Old camp, and you'll have to stick with New Camp
Actually, no, you can still join the old camp even if you do this (I do this every time for my "all camps" save I make before committing to a faction). It also gives you the ability to talk to Gorn (er, I think) later on for a share of the loot.
