Nothing wrong with the Sunnto computer, from what I have read from it's owners (I have not used one yet, won a Viper over Christmas and will be testing it soon). The real issue is do you need one at this stage of your diving. Some will argue that you never need one but that's another thread. While I do like diving with one, at this stage in your diving you really only need the essentials. BC, reg, gauges, exposure suits, bottom timer and a set of dive tables. Learn to dive with these, get some experience and then buy other equipement as you understand what YOU need and want.
While I am on the "what not to buy" subject, I would suggest that you only buy the bare essentials -mask/fins/snorkle and maybe a wetsuit and rent or borrow equipment for at least the first 10 dives. Use different types/brands of equipment and see which one suits you best. Don't rush in to a purchase of anything, buying slow is usually buying wiser.