Sjadbek is generally an honest, straightforward, let's-not-mince-words type - not quite as blunt as Galmar, but definitely nowhere near as esoteric as... well, let's say Septimus, if he were sane. Worships Stendarr primarily, but is not a Vigilant of same - he went through the Companions in full trusting Kodlak's assurance that there was a cure. Somewhat bloodthirsty, but feels a sense of "what could have been" regret anytime he kills a legionnaire who happens to be a fellow Nord.
Respects and is fiercely loyal to those who've helped him, befriended him, or fought with him. Loathes the Aldmeri Dominion and disdains what the Empire has become. Dislikes those who have personally betrayed him, but understands that there are some times when betrayal is necessary, even good (he is a Stormcloak, after all), and because of this sides with P rather than D&E. Likes mead, especially Black-Briar Mead.
Won't kill or harm those who mean him no harm, with the exception of Grelod and then only because "Stendarr told me it would spare Skyrim future bloodshed" (read: I, the player, knew it was necessary in order to initiate the destruction of the DB).
Is leery of Khajiit and "untrustworthy" Bosmer and Altmer (read: those not inside the walls of Whiterun or Windhelm, as he trusts Balgruuf and Ulfric sufficiently), though generally will not voice these sentiments, at least not while sober. He has little problem with the Dunmer - his thoughts are basically as follows: "They're refugees from Morrowind, not Imperial spies, and if they were, they're obviously not doing a good job of it. Leave them alone, Rolff, isn't it enough they live in the Gray Quarter?".
Believes the Argonians are being kept out of Windhelm to protect the Dunmer (rather than the Nords) from them on account of the Black Marsh invasion of Morrowind after the Red Mountain eruption, but he personally has no problem with Argonians. And of course, all the human races are fine by him. Indeed, there's one Imperial in Riverwood he finds quite fetching... now if only that pesky Bosmer and milk-drinking bard weren't an issue....