I wouldn't say that it's bad, but it's not as good as Seasons 1-3. Seasons 4-5 don't have the same feel as the earlier seasons, but there's still enough of "the feels" that it still feels like Primeval. It's all rather subjective though, but if you really wanna know what happened after the end of Season 3, I'd recommend you watch it, just for closure. I'd also recommend you watch the Season 4 webisodes on Youtube as well if you want to get a feel of Season 4 before you watch the season itself.

Ok thanks. I have watched episodes 1-3 thus far i think its better than 3 not as good as 1 and their all dwarfed by 2.

I'd recommend it if you've watched up to season 3, in my opinion it my not have the same energy as 3 but the narrative is much stronger then most seasons, Connor and Abby are at their best during season 4 and 5 as thay have the most impact on the plot and the way it ends between the two really brings the series to a mostly satisfing conclusion. Despite saying that, it dose not reach the highs of season 1 and 2 for me personally but I'd recommend it!

Made it for you

Series 4 is great, it has a great serial arc and the last episode is one of the show's strongest series finales in my opinion. It's definitely a bit of a soft reboot but it feels fresh and exciting and the mysteries woven in throughout really keep you guessing. I personally think Series 2 is quite overrated, in that the writing was not as a strong as Series 1 and things like Leek's menagerie and Helen's big plan were quite poorly explained. Don't get me wrong, I really enjoyed it but something about it didn't quite hit the mark the way Series 1 did perfectly. I honestly think it's that decline in quality of scripts that made cast members begin to leave.