If I am completely logical, I would give this show 3 stars, but emotionally, I give it 4/5. I was drawn in and became invested in the characters, and it will always hold a special place in my heart, like that one ex you always smile back on yet shake your head because it's a damned shame.
The concept is unique, with a bisexual succubus as the lead character, and refreshingly sex positive, with a few hiccups. People complain about too much sex, but they are ridiculous prudes; she's a succubus, and she feeds on sexual chi. If anything, there is way too LITTLE sex. She should be having sex at least every episode, and this is not the case. I don't see anyone complaining about Kenzi eating all the time. Sex is Bo's cuisine. You don't like it? Don't watch a show about a succubus.
Ahem, that aside, I wish there had been better writing, wittier lines and more clever dialogue for these characters. There was so much potential wasted here. I hope to see a reboot with a better team, though I would keep many of the original actors if possible. I enjoyed the corny, campy fun of this series, to a point; as it went on, the plot holes and silliness became too great. I also found many of the nemeses to be anticlimactic and underwhelming after mysterious and intriguing build-up, which made it more fun to rewatch.
On a personal, petty note, I cannot stand Lauren. She is like a big wet mop in all but a few scenes, though she really shined getting drunk with Dyson and Vex in Season 4. That was priceless.
The inclusion of (spoiler alert) Dyson's son in Season 5 where Bo has sex with him before she realizes the connection is pretty disgusting, as he's quite young; I could have done without him, a teenager, having sex with grown adults sometimes hundreds of years old. Gross. This concept has been around in other shows (Buffy & Angel, for example) but was much better done to at least seem less gratuitous.
Kenzie is incredibly endearing, Trick is fascinating, as are many of the other fae, and there are so many episodes which are great for rewatching on a cozy, rainy day. Turn your brain off to enjoy this romp in faeland, then let your imagination run wild as you ponder how awesome it could have been, if only...