The technical arguments for Dalvik I remember are twofold:
(a, minor) the dalvik vm is a closer fit to the underlying cpu (being a register-based vm iirc) which makes it simpler to implement and/or a little more performant
(b, major) the dalvik vm (contra the jvm) is designed to more-easily support the "single vm instance with multiple logically independent apps running in it" model; this reduces the vm-induced memory overhead b/c the vm and any system-wide libraries are only loaded once.
There's probably also some truth to the trademark argument.
(a, minor) the dalvik vm is a closer fit to the underlying cpu (being a register-based vm iirc) which makes it simpler to implement and/or a little more performant
(b, major) the dalvik vm (contra the jvm) is designed to more-easily support the "single vm instance with multiple logically independent apps running in it" model; this reduces the vm-induced memory overhead b/c the vm and any system-wide libraries are only loaded once.
There's probably also some truth to the trademark argument.