JuiceDefender Ultimate, which I bought from Amazon AppStore for $1.99, caused my LG Esteem to severely slow down. I installed, uninstalled and reinstalled JuiceDefender and JuiceDefender Ultimate a few times to compare the before-and-after results on my phone, and I can confirm it was definitely JuiceDefender Ultimate that were causing the slowdown. The basic version did not cause any noticeable slowdown.
Furthermore, JuiceDefender Ultimate would often freeze and crash my LG Esteem when I opened the application. The app would freeze as it was loading its settings, and then the phone would crash and automatically reboot. Only the Ultimate version was causing a lot of problems on my LG Esteem. The basic version seemed to be more stable and did not crash my phone.
It is possibly JuiceDefender Ultimate was having conflicts with GO Launcher EX, an excellent home-screen replacement app I had installed on my phone. However, between JuiceDefender and GO Launcher EX, I choose Go Launcher EX. GO Launcher EX is a far, far superior app than JuiceDefender. I consider GO Launcher EX as a must-have app and JuiceDefender as a headache.
Another thing I despise about JuiceDefender is that, when I upgraded to the Ultimate version, I had to install three different versions of JuiceDefenders to use the Ultimate version. I had to installed: (1) the basic version, (2) the upgrade key that I purchased, and (3) the Ultimate version that would show up only by combining the basic version and the upgrade key. Those were three separate apps, which took up three slots on my app page. If I uninstalled either one of those three apps, the Ultimate version would stop working. The upgrade process of JuiceDefender lacks elegance.
The basic JuiceDefender worked fine on my LG Esteem. However, I have uninstalled both the basic and Ultimate version. I felt the battery life conserved by JuiceDefender was marginal at best. They were simply not worth the troubles they had been causing on my phone.
Ever since I had uninstalled JuiceDefender, my phone has been running smoothly without a hitch.
P.S. My phone is not rooted.