More percent of stakes goes to senior members like Sr member, hero member or legendary under bounty campaigns. But except for few cases, their performances are similar to those by junior members like member, Jr member.
The signature spaces are bigger and more prominent for higher ranks, but also the fact that they've been here longer does give their opinions more weight really. If a load of Legendary members were backing a project, and a load of Newbie ranked members were backing a different project, I'd definitely look at the Legendary one first.
it is really hard to get merit
Agreed. I have been struggling to get merit as well. I did make a post in the Economy section recently which got me a couple of merit, so it might be worth looking outside the altcoin section. But it's by no means easy. I would expect I'd need to start maybe 100 really good new threads in order to progress up to Senior. For lower ranks obviously the merit required is less, so comparatively less onerous a task.