I guess it depends what you are after. eHarmony is definitely one of the better sites, I found the users on eHarmony were more interested in a relationship and personally had 5 great (1 amazing) dates, the 1 is my partner now. Some of the free sites, like POF (plenty of Fish) were filled with people 'having a laugh' I guess thats the cost of a free dating site.
As for current prices http://datingpriceguide.co.uk/eharmony-cost-uk/ pretty much states the latest prices - if there are any discounts or promo codes they will be listed aswell.
Like anything, I think you have to try it yourself before you can judge! Well....most things
There is a free communication event occurring on the 18th April, so go sign up and see what you think for free - you have a bit of time to prepare!