Since you mentioned that you have a Mad Bomber suit, then I'm assuming that you're using it with CTR Max.

Sorry for the wall of text, but consider this the bombing guide for the DR, if you want to.

With that much CTR, by stacking and spamming it, you should be able to keep three going at a time, approximately.
Unlike other bombs that you can spam without thinking, with the DR, you want to stack them so that the outside edge of each bomb overlaps on the inside of the previous one. Like using the DBB, you want to stay inside of your bomb radii, so that enemies will move into them to follow you. Placing them and moving away to get things to kite through the bomb isn't very effective, except in arenas where there are too many enemies to move between them safely. Against less than an arena-size mob, if you drop a bomb and move away to kite things through it like a mist bomb, you'll probably only get 2-4 hits which isn't really worth doing.

When I stack DR bombs, I make a triangle pattern (sort of) so that each bomb that I place has it's outside edge passing through the middle of both of the last two bombs I placed, one about to go off, and one still going off. Doing this while circling one enemy (like a giant lichen colony, or even a lumber) or moving in and out of a group of enemies can do MASSIVE damage.

If you place them in the same place, or too far apart, they will not score many hits. The idea is to keep the monsters turning to follow you, but moving through the center of your bomb groups where the most projectiles are spinning.

It obviously does low damage to fiends and undead, but the only things it's really terrible against are kats and devilites.

It powers through:
Jellies - obvious, especially in groups
Giant Lichens - bigger targets are the easiest to hit with it, just watch out you don't get hit too much
Lumbers - easy too, circle and wait for them to die
Groups of Scuttlebots - easy too, stack as described above
Any kind of beasts - stack as above; chromas will just keep turning to follow you, and wolvers will dodge behind you and into the bombs over and over. If they move away just keep placing bombs until only the ones that move away are left and you have to go get them
Gremlins - just watch out that you don't get whacked with a hammer; gremlins should go down easy to this bomb (I just did a fire decon zone twice in a row at depth 25 and killed groups of more than 10 burners very quickly this way.) Ignore the menders and slowly move your bombs closer and close to them. The pack will follow you and you can easily out-DPS them as you go. DON'T leave the others alone to chase menders. If you damage the other gremlins, the menders will stay still to heal them and make easy targets.
Gun puppies and polyps - Since they don't move, place one or two bombs 1.5-2 squares away so that the inside and outside projectiles both hit as they pass. In tier 3 one bomb can usually take out a polyp if you are playing solo, most often one is enough in tier 2 as well against gun puppies.

It is reasonably good against:
Zombies - even at 10 damage per hit in tier 3, stacking the bombs in groups of zombies kills them about as fast, or faster than shock damage. It would be more effective than VT if VT's initial small blast didn't do over 200 damage in FSC. The DR does about 10 damage per hit at a much faster rate than shock, whereas shock does 20-30 at the bottom of tier 3 to zombies. Even though these are small numbers, you can hit large groups very quickly with both of these. It can be tedious sometimes, but it works and it can be hilarious fun.
Grievers - This may SOUND insane, but consider that every time a griever is hit while charging an attack, it stops attacking. As long as you set up a few bombs before they get to you, and keep placing them, getting mobbed by grievers while using the DR is quite safe and hilarious. Killing grievers with a DR without taking a hit will make you feel like the king of using the wrong weapon to get the job done very well.

When the patch that reduced the speed of the DR came out before, I made a reference to someone telling me about using it for Vana in phases 1 and 3 and I joked that I wanted to try it to see.
Since then, I have tried it, and it works faster than a Final Flourish or BTB with ASI med fighting him solo (for phase 1 at least.) It's obviously not an IDEAL weapon for vana, but it was fun to try, and it certainly worked fine. It's useless for phase 5 though, and other weapons for the fight are overall more useful, so I'm not saying I recommend it, just making a funny note of how it can work.
For phase 1, you can circle him and place bombs to constantly hit him for 31 damage times about a billionty and he won't be able to follow you enough to attack if you stay close. Getting him to phase two without letting him attack once was easy to do with the DR.
For phase 3, stay back a bit and dodge carefully. It reaches past his fireballs and he will take fairly consistent damage so long as he doesn't charge out of the bombs too much. It's a bit tedious, but it's better than trying to take him down solo with an AP now.