I like that it's easy for my accounting department (and me!) because we're using spreadsheets extensively at work right now so this makes our life easier! The only thing about lightz as of yet - not sure if they've fixed any bugs or what but sometimes when you try typing something into one cell which has no value other than '1' then suddenly every single number will be 1 instead? It happens very quickly too where everything changes from normal calculations etc..
You have to go back through your entire spreadsheet/sheet again before continuing with anything else. This doesn't happen often though just once maybe twice while testing out things during early access phase so don;t worry unless its happening more frequently after launch I'd say thats probably just how some people use excel haha!! But otherwise good tool overall definitely useful especially since most companies are.