Model driven software engineering (MDSE) has shown to provide mark improvement in productivity and quality of software products. UML is a standard modeling language that is widely used in the industry to support MDSE. To provide tool support for MDSE, a large number of UML modeling tools are available, ranging from open-source tools to commercial tools with high price tag. A common decision faced while applying UML in practice is the selection of an appropriate tool for modeling. In this paper we conduct a study to compare three of the well-known modeling tools: IBM Rational Software Architect (RSA), MagicDraw, and Papyrus. In this study we conducted an ex- periment with undergraduate and graduate students. The goal is to compare the productivity of the software engineers while modeling with the tools. We meas- ure the productivity in terms of modeling effort required to correctly complete a task, learnability, time and number of clicks required, and memory load re- quired for the software engineer to complete a task. Our results show that Ma- gicDraw performed significantly better in terms of learnability, memory load, and completeness of tasks. In terms of time and number of clicks, IBM RSA was significantly better while modeling class diagrams and state machines when compared to Papyrus. However no single tool outperformed others in all the modeling tasks with respect to time and number of clicks.