It's pretty neat, not going anywhere ground breaking but the girls are all appealing and the author found a way to force beta-kun into lewd situations in a fun way that gives free reign to random, out of place and out of character behavior. I really like the changing forms aspect, from a action point of view it keeps the MC from becoming stale and makes you want to see what happens if so-and-so gets his chain and anytime a new girl shows up you know there is going to be an excuse to show off what he turns into when she nabs him. (And then what she must pay for doing so later
)
As for Bell, I wouldn't count her out of the fight just yet - Yamashiro isn't the type of character to pointlessly talk up someones abilities (see chapter 100), and no one ever said where the life force she takes goes.