A study conducted by MGMA indicates most doctors surveyed who have implemented electronic record systems are satisfied or very satisfied, and many report increased productivity and reduced costs as those systems are optimized, according to Modern Healthcare.  The full MGMA study may be downloaded here (registration required).  This report is highly recommended reading.

The study, funded by PNC Bank, tabulated over 4,500 responses from a variety of organizations representing over 120,000 physicians, over half of them in independent private practice. Of the respondents, 16.3 percent believed they had optimized their EHR.   One surprising finding – independent physicians are farther along in the process than hospital-employed physicians: 

Finding independent practices further along in EHR optimization than IDS- and hospital-owned practices might seem surprising at first glance. As components of larger systems with greater access to financial and technical resources and expertise, IDS- and hospital-owned practices would seem more likely to lead rather than trail independent practices in EHR adoption. Yet, aspects of hospital and IDS-ownership may slow EHR adoption; it also may slow integration of EHR with other technologies

The leading barrier to implementation of EHR cited was “Expected loss of productivity during transition to the EHR system”, followed closely by “Insufficient capital resources to invest in an EHR.” 

Most telling is Figure 12 in the report, which shows 85.8% of "optimized" EHR users satisfied or very satisfied with their systems overall; 56.5% of such users satisfied with the ability of the EHR to decrease practice costs; 61% of such users satisfied with the ability of the EHR to increase provider productivity; and 60.8% satisfied with the ability of EHR to increase practice revenue.  MGMA concludes:

These data indicate that EHR users find reaching full optimization of their system produces benefits, and that they are more likely to perceive these benefits than other users. Efforts to optimize an EHR implementation are likely to produce tangible benefits for a majority of EHR users.