I think both Austrailia and canada was asked about both projects but for there own reasons decided not to invest , this i think must be about the deal being offered by bae which i guess was about how much money they could make out of the deal, not because of capabilities of the type 45 which i would say when fully armed will be the best aaw destroyer in the world ,sampson radar i would say is more effective than the aegis system specialy against a saturated attack due to the fact the arrays are fixed.
Very off topic as we're on Canadian subs but just to touch on points about the Type 45 - against *saturation* attacks, the bottleneck is usually how many targets the entire system can process simultaneously or very nearly.
The two ships are totally different in this respect - the Arleigh Burke uses SPY1-D with four fixed arrays which are electronically scanned to build up a picture around the ship. The Type 45 has a pair of arrays back to back, which are rotated mechanically, although the beam from each array is steered electronically while the arrays are rotating.
Where they further differ is that as of this time, the AB's use a semi active radar homing missile which requires terminal illumination by a narrow beam target illuminator, vs the active seeker in the Sea Viper missile (Aster-30)
Both missiles have an autopilot which can take updates from the guiding radar and neither require illumination til the last few seconds of flight. I don't know how many channels the Arleigh can control but the Darings are said to have 16.
Both ships can therefore squirt off a fair few missiles in all directions - it's in the last few seconds of engagement where the Daring potentially scores points as of course, each missile comes with it's own seeker. The Arleigh relies on a target illuminator to guide the missile in it's last few seconds and it's the availability of the TI's that limit the amount of targets an Arleigh can process.
However, and it's a big however, that illumination is only needed for a short time, and the TI's can apparently slew automatically to the next target very quickly. In extremis, there's a mode which allocates time between targets for an illuminator allowing it to point out multiple targets more or less simultaneously, although obviously the update rate will fall correspondingly.
I'd be inclined to talk up the SAMPSON's performance in cluttered littoral areas against jamming and numerous low level targets however - it's more of a clear cut advantage as the SAMPSON is 30 years younger and is an AESA radar with all the agility in frequencies and with the beam forming capabilities that allow it to do some remarkable things.
Bear in mind I have no practical experience and this is just scattered fragments of what I've come to understand. Other people can correct me I'm sure and probably aid my understanding of it all greatly,
Ian