Who is more credible: Jack Mintz or the NDP's Finance Critic?

Letter from Denise Savoie:

“Dear constituent: I have spoken with Judy Wasylycia-Leis, our party’s Finance Critic, she is confident that the government’s estimates of future tax leakage are accurate.”?

From: Jack Mintz
To: brent.fullard@rogers.com
Date: Tue, 28 Nov 2006

I do want to point out that there is a serious flaw in some [tax leakage] analyses especially on the taxation of pension and RRSP accounts. Finance was not right to treat the impact as zero