I liked most of the movies individually, but as a group....I have never seen such a disregard for continuity in any franchise. As for The Source...well I really didn’t like their interpretation of the "One". Basically it didn’t matter if there was one Immortal or one thousand left alive. One special one had to beat the guardian. I liked it much better when it was one Immortal left standing.
As for the series...I loved it, but at the end it wasn’t fun, exciting and cool to be an immortal any more. It became a burden. Look at the last episode when Duncan sulks off to no one knows where, leaving everyone on the barge shaking their heads. It could have ended better.
I'm still looking forward to watching though.