You didn't say what your budget is? This will be the key aspect to any advice you get. Money no object, I would be looking at a Scorpion. I've never heard anything bad about them, other than people complaining that they can't afford one.
However, otherwise if you are looking at the mid range of the market, I would suggest either of the following:
Tornado - They are a very good dive boat, I know of several clubs in Ireland who have them. Very good deep V that gives a comfortable dry-ride. www.ribs.co.uk
Ribcraft - Very well built strong rugged boat, Deep V hull is also brilliant. Have heard nothing but good reviews. www.ribcraft.co.uk
Parker Ribs - Look a very good boat. David B and Andre who both post here are UK dealers for them, so I'll leave them tell you more!! Put in a search for them in the gallery for some nice pics.
I myself was in the same predicament, 6 months ago. As you can see I've gone for an XS-600. Will be collecting the boat in London in 2 weeks time. Will be posting a full review of the boat here and as far as I know it will be the first XS-rib on Ribnet. Very well priced boat. Built using commercial grade materials. Uses consoles, A-frame and tubes from Tornado, but with a different hull based on the 3-rail hull design of the larger Tornados (but not built by Tornado). See for yourself: www.xs-ribs.co.uk
Hope this helps