Personally, I dislike Beagle AP. 4 hexes is too low for its primary purpose of ferreting out hidden units, IMO. So with that in mind, I love Bloodhound AP for its larger range. And of course, it being able to penetrate most stealth systems is definitely a plus. Only thing I find irritating is the 3 slot size; makes it a bit awkward to build into units, especially certain omnis.
Angel ECM I'm a bit more ambivalent towards. Blocking Streak lock-on is nice, but since the launcher can still fire as a standard rack, it's not that huge of a deal. So unless I'm dealing with a lot of Boosted C3 or ECCM, Angel doesn't really have any value-add. On the other hand, it is only a half ton more over Guardian and no change in number of slots, so depending on the unit it could be worth upgrading.
And in both cases, taking the upgraded versions of the gear would depend on timeline and availability, assuming a campaign instead of a pick up game.