The Congressional Research Service (widely respected for its objectivity and thoroughness), has dug deeply into Merrick Garland's judicial record.
Here's a summary of the 78 page report, Judge Merrick Garland: His Jurisprudence and Potential Impact on the Supreme Court:
This report provides an overview of Judge Garland’s jurisprudence and discusses what the impact on the Court might be if he, or a judge of a similar judicial approach, were to be confirmed to succeed Justice Scalia. In particular, the report focuses upon those areas of law where Justice Scalia can be seen to have influenced the High Court’s approach to certain issues, or served as a fifth and deciding vote on the Court, with a view toward how Judge Garland might approach those same issues if he were to be confirmed. The report begins with his views on two overarching issues—the role of the judiciary and statutory interpretation. It then addresses 14 separate areas of law, which are arranged in alphabetical order from “administrative law” to “takings.”