I have heard that Alter Halpern, a Rabbi in England, published an article or kuntres presenting issues with Marcus Jastrow's Dictionary (for the Talmud, midrash, targum), i.e Sefer HaMilim.
What were his specific issues, and does he go so far as to assur it?
I know that Rav Yaacov Kaminetsky said that it was okay to learn from it.