UltraEdit is a great product, I used to use it extensively in the past. I don't think it had the 'compare files' feature back then.
This effort to compare stored procedures has gone through several iterations, the most recent of which uses a recursive CTE: http://www.sqlservercentral.com/scripts/TSQL/66074/. You can also check out the blog entry here: http://jessesql.blogspot.com/2009/02/comparing-stored-procedures-part-6.html, which explains a lot of my thought process, and demonstrates some performance charting.
Using the most recent version above, you can run this query below on the results to achieve a visual comparison:
Seq1_Line = ISNULL(LTRIM(STR(S1.CodeLineNum)), '')
,Seq2_Line = ISNULL(LTRIM(STR(S2.CodeLineNum)), '')
,OrderBy = ISNULL(S1.CodeLineNum, S2.CodeLineNum)
FROM Seq1 S1
FULL OUTER JOIN Seq2 S2
ON S1.CodeLineNum = S2.MatchLineNum
ORDER BY OrderBy