The Sunny and the Helios II inflatable kayaks are about the same length width and weight. Which one is best for you depends on how much of the time you would be paddling solo versus with a partner. Either kayak can be paddled solo or double, but the Sunny is a somewhat better solo kayak and the Helios II is a somewhat better double kayak.
Here's why. The Sunny seats tie-in and the boat can be setup with a single paddler in the middle of the boat, with the other seat replaced by an adjustable footrest. Being in the middle of the kayak means that the boat is balanced in a crosswind, and neither end will weathercock away from the wind. The Helios II can also be paddled solo from the fixed aft seating, and to counteract the weathercocking of the kayak the optional rudder can be used -- by taking a cut into the crosswind. But we would give the edge to the Sunny for solo paddling.
For double paddling the Helios II is a little better than the Sunny because the paddler in front will stay drier paddling into a chop. They sit a little further aft in the Helios II than in the Sunny, and the Helios has more foredeck protection. The Helios II's optional rudder also gives very positive foot control of steering when paddling double, whereas the Sunny requires paddle steering.
So if you are going to be paddling primarily solo, but occasionally double, go with the Innova Sunny. Conversely, if you are buying your inflatable kayak for double paddling, the Innova Helios II is hard to beat. The Helios II has been picked for the Readers' Choice Award from Sea Kayaker magazine for the "Best Inflatable Kayak" both times the 3-year award has been given -- for a term of 6 years.