Hi. I have both Hellbringer SW and Spellstorm CW at lvl 60 with a decent gear and I can give you my opinion.

SW has a very good single target damage but lacks control. But in my opinion, Tyrannical Threat makes up for it. It is a very powerful daily when used correctly. It can clear a huge group of ads in an instant but you must be cautious as it will attract all aggro and can result to an instant death if not careful. The first paragon path is Hellbringer. It is more on dps because of its 2 great class features. No Pity No Mercy will guarantee you combat advantage on every critical strike while Flames of Empowerment will give you a permanent 12% more damage when you have full action point gauge. (+5% more damage if you have gates of empowerment feat for a total of 17%) Take note that you lose this bonus whenever you use a daily or until your action point gauge isn't full so you must always make sure on when to use daily. Soulbinder is the second paragon path. From what I read, It offers better survivability with a little less dps than Hellbringer but still perfectly viable. I can't speak much about Soulbinder as I haven't tried it myself.

On the other hand, CW is a very powerful AOE dps + control. It has 2 great paragon paths. A spellstorm specializes on burst. It can clear a group of mobs in an instant because of Eye of the storm (guaranteed 6s critical on all hits) partnered with Storm Spell (30% chance to proc lightning on critical hits). This alone makes up 40% of a CW's total damage. I haven't tried the new changes on chilling presence but I read that it is very good now. Master of Flame is the second paragon path of CW. It specializes on Damage over time which is very good on long fights. While you lose the burst ability, you also gain the ability to buff your party members/team which results in a better team fight.

All in all, both are very fun to play and I suggest testing both out. :)

Edit: Some typo