We use Dr Xiaokun Kelvin ZHU's 'jms' version 1.0 JDBC driver, and find it to be reliable and fast, though inefficient in terms of memory management. Dr. ZHU recently released version 1.3 of the driver, and intends to write a new, more efficient driver. Moreover, the 'jms' drivers are distributed with source code, allowing point fixes and debugging where necessary. We have found the mySQL database server to be robust. Though there are numerous bugs, of a sort we would not expect to find in a mature commercial product, the developer is responsive.
Maintenance is good, with regular patches roughly quarterly update releases.
For-fee support is available, and reasonably priced. To the extent possible, we have simulated transaction logic in application. The choice of development tools often has a multiplicative effect on the rate at which code is produced. Having spent substantial time evaluating both solutions, we chose the basic Sun product over graphical IDE products. An effective debugger can reduce the number of cycles.