Sentry Domi - easy semi-afk generic mission workhorse. Does a great job with just a T2 fit.
Gila - never tried one
Ishtar - handles level IVs well with advantage it can also rat those annoying anoms with gates banning battleships
Rattlesnake - on paper max DPS (up around 1800 with good skills) but in practice hard to fit and fly. Probably the best blitzer if you have the skills and are prepared for the workload.

rattlesnake seems like it might be a fun ship to fly.

Thought that, too. Glad I read your post so I remembered I bought one a while ago...in the end it turned out to be crap for most stuff now it's more than 25 jumps away and I won't bother with it in the future.

Dominix is the best sentry sniper due to the bonuses, if you try a Targetpainter instead of a third Omni, you won't regret it. But overall Marauder > All, as long as you stay in there "native" environment, Golem does a pretty good job everyhwere.

TP sounds like a good idea on paper but in fact you just wait for it's cycle time far too much.

Third omni can be scripted to provide on demand stats and it's always active (though I wish it's cycle time was lower)

In regards to the Rattlesnake, yes you can get almost 1800 dps; but that dps is almost evenly split between drones and missiles. So the actual damage application is slower in my opinion than a Macherial or Paladin. For best isk/hr, you can't go far wrong with the Macherial, Paladin, or Kronos.

Rattlesnake is a great ship for missions you can have sentries and heavy drones, MWD for mobility, cruise missiles and target painters that help damage application for both weapon systems, and a great tank.

missiles, especially, without a speed bonus = delay on dps, plus if you slip up on counting you waste volleys.

With a Rattler its not such a big issue as in missile only ships. You can target the BS with missiles and small targets with sentries and then each time a BS is down near structure move the missiles to a new BS and finish the current one off with your sentries.

You end up with a high workload but it lets you actually apply all that DPS without really wasting any.

I either use my 1154 dps Paladin with pulse lasers, or my cruise/gecko 1375 dps Rattlesnake

try some rapid heavy's instead of the cruise missiles.. you will be pleasantly surprised.. with precision they obliterate frigs

at range sentries take care of frigs no problem, up close a gecko will volley most frigs. not sure rapid heavies are all that useful.

The loading times cripple them. Great anti-cruiser/frig weapons for a battleships but for missions there are better options.

On the whole a gunboat will be faster than a missile boat simply because of missile flight time. Guns hit instantly so a gunboat will clear the grid faster than a missile boat. The mach wins because of both this and the fact it warps as fast as a cruiser right out of the box.

In regards to the Rattlesnake, yes you can get almost 1800 dps; but that dps is almost evenly split between drones and missiles. So the actual damage application is slower in my opinion than a Macherial or Paladin. For best isk/hr, you can't go far wrong with the Macherial, Paladin, or Kronos.

The domi is a great "cost effective" boat. however, "cost effective" is so plebeian.

I guess my answer somewhat depends on where you decide to run missions. the 3 highsec agents are in caldari/amarr/minmatar space, with the two in amarr/minmatar space being preferable. However for both I would suggest a Machariel. and given they are so cheap you might even want two, one AC, and one arty fit. Swapping fits is pretty easy, swapping ships is even easier. beyond that I like the paladin, although don't think it would be as useful in minmatar space, I would probably just fly a mach out there. might want a vargur, but I feel like the mach will just do better in most cases.

if you really want a drone boat, the rattlesnake can do some cool things, but I find the combination of missiles and drones to just be annoying.