First, if you look at the reward allocation percentages, I think signature campaigns are more worth following.
Second, the advantage of participating in a "signature campaign" is that fewer people participate than others. More importantly, follow the manager who pays for your hard work at the end of the campaign.
Beyond that a well paid and well managed signature campaign adds to your repertoire on this forum. On the other hand people trying hard to get into altcoin campaigns are spamming the forum with low quality replies get blacklisted by managers and frowned upon by most members.
It is defenitely satisfiying to get paid the promised amount at the weekend of a campaign but it is equally frustrating to join an altcoin campaign to not be paid a single buck. Hence I never suggest any newbie to join any of the altcoin campaigns but keep themselves limited only to bitcoin paying ones. But for that they would first have to grow their account's ranks.