Sinnott did a fair job. But as Jimmy says, history will remember him much kinder than the reality. Let's not forget the full calendar year we went without a clean sheet under him, or the 40 odd (mostly sh*t) players we went through in his first season (yes, I realise the irony of bringing that up now...), or the 7 out of 10 cup campaigns that ended with a whimper against lower league teams, or the fact we spent a lot of money on promotion and still never seriously challenged for the title that year.
On reflection, I'd say years 1 and 5 of his reign were pretty wank, years 2 & 3 par, and year 4 a good achievement.
We definitely played some great football in Conf North under Sinnott which was fun to watch (mainly against the fodder in the league while struggling against anyone good) and you still have to spend the money well, which he certainly did the year we went up - scoring nearly 100 league goals. But there is now a bit of a danger of him being turned into Bill Shankley, because of Grahame Rowley's inability to appoint a manager since, when the reality was nowhere near.