How good was he? He seemed like a great puncher, but he didn't seem to have that many impressive wins.
I ranked him #13 for the 1890's in Rummys top 25 boxers in each decade thread. In that decade alone, he went 89-5-4, and was 74-3-2. Wins over Choyinkski, Slavin, Godfrey, a 10lbs heavier Goddard, Bonner and 2 vs Ruhlin, is more than a little respectable. As is his draw with Tom Sharkey.
I think Maher was a top P4P puncher. You could add O'Donnell, Klondike, C C Smith, Russell and Kennedy to his win ledger. The draws with Hall and McAuliffe were in actuality wins while his only losses in that 11 year span were to Fitz and Goddard, the Goddard one revenged. He was also very unlucky, perhaps jobbed out of a KO win in the first Fitz fight.
He is one of those fighters whose resume looks much more impressive when you understand the context of the time.
Several things about Maher: 1) He was born in 1866 not 1869 so he was past prime by 1900. 2) He was an alcoholic 3)He would fight anybody. 4) His record against black fighter was immense. Just out of the amateur ranks he retired in an exhibition against the great Peter jackson and then went on to beat Godfrey, Craig, Hayes, Stevenson, Klondike, C C Smith, Butler and others. 4) He was in or around the light heavy mark. 5) He looked likely to beat Sharkey when the police interferred 6) He was an extremely clean fighter, never even clinched. 7) His draw over twenty with Ruhlin is rated one of the greatest heavyweights by thoes who witnessed it. 8) Counting exhibitions, he likely had 300-400 fights. He is greatly underrated now, in his pomp, he was the most popular fighter in the World.