The thing about Bards is they have some of the best defensive buffs in the game. Then they have enough UMD to hit the rest. Displacement, Haste, UMD'ed Stoneskin wands, GH, Blur, and Freedom of Movement. With a decent build, you'll have 500+hp, and combined with that and better self healing than any non Divine Caster and you have a character that is very tough to kill. They also have the best offensive buffs in Haste and Rage, and the songs, especially once you get into Fatesinger and pull Reign, Dirge, and Siren's Song/Poof.
Mirys lands about 150-200 point cure criticals, with no metamagics. I also have a decent investment into Healing amp however.
Then they have decent, if not spectacular, saves, and due to the currently lacking higher levels, are well suited for a splash or two, with the common 16/2/2 Warchanter serving as an example. Splashing Rogue for evasion is useful, like Mirys has done, and they can with some INT investment even handle trap duties. I didn't because I didn't have the points to invest. If I had a 36point build, I'd consider it. Two Fighter will mitigate the feat issues as well.
The problem is they take awhile to get to their comfortable power level; they only get the 7 basic feats pre-20, and the two Epic feats. So if you're doing TWF Khopesh builds, like Mirys, you hurt for feats. 5 feats are required for her melee, with Toughness and Extend filling in. Extend is basically mandatory, due to the extensive use of short-term buffs.
All Bards also have some CC, with caster-specced ones being just shy of matching a Wizard. But melee ones still have song-CC from Enthrall or Fascinate, Capering Song, and Siren's Song.
Another thing is for the pugging members of the guild, Bards are pretty much universally welcomed into groups, almost as much as Clerics or Favored Souls. Their buffs largely stack with everything.
I'll admit I disliked Bard in the lower levels, but partially I wonder how much was Bard, and how much was a lack of experience with the class and a general burnout on DDO. Once I got into the new stuff in Eveningstar, Mirys became fun again. I think mostly it was the burnout, as I had mutliple characters stuck in the same level range and I was running the same stuff over and over and over.