I use the SQL Developer tool provided by Oracle, and for day to day development, it's good enough, however TOAD obviously has more functionality and better DBA and performace monitoring features. I developed entirely in SQL Server for several years and for the past two years or so have been splitting my time between several smaller sized SQL Server projects and a large Oracle 11g data warehouse. When it comes to just writing SQL queries, the two platforms are very similar, and a developer new to Oracle may at first be overwhelmed by all the thick books and tend to overestimate the number differences. However, it's also easy to underestimate how frustrating those minor differences can be when you find yourself in a jam. I can recall early on how I would be sitting with my laptop in a project status meeting, answering questions about the data model and performing ad-hoc query requests. My screen would be displayed on a projector, and I'd be fumbling with the syntax of a fairly complicated Oracle SQL statement while management and business analysts patiently sat by watching. Fortunately those awkward first few months are behind me, and I'm now about equally proficient with both SQL Server and Oracle, at least in terms of SQL. Now in terms of PL/SQL vs T-SQL, database administration and architecture, there are more significant differences between SQL Server and Oracle and a more significant learning curve.