I've said some nice things about 30-30; in the interest of full disclosure/even-handedness, I'm going to list the downsides. This is more about the rifle, a Marlin 336W:

1. Heavy for size. It is short and handy, but just a tad heavy. I'm used to a very light muzzleloader, and before that a Savage 111F in .270 which was quite light. The Marlin feels heavier than either of those, but it is shorter - and short is a virtue.

2. More prone to operator error. I carry it into woods with round in chamber and set at half-cock; I need to remember to TAKE SAFE OFF while in the tree. Why? That safety isn't silent, whereas I can cock the rifle silently. Worse - you can have safety on if you squeeze trigger, hammer will SNAP home. Took a buck last tuesday. I got deer in crosshairs and dropped the hammer on the blasted cross-bolt safety, having forgotten to put it on Fire. With a bolt gun, I wouldn't have been able to sqeeze trigger/make noise; with the Marlin it made a very loud CLICK as hammer hit home, and no discharge. Had to re-cock, turn off safety - that not-silent safety - then put bullet through buck's heart as he tried to figure out where noise came from. With my old Savage, I simply wouldn't have been able to sqeeze trigger.. and could have silently slipped off the safety.

3. In cold weather, it's cold. All that nice-looking exposed metal at receiver is cold in the cold.

4. With bulky gloves, getting fingers into trigger guard/lever can be a little awkward.

5. Inconvenient to load/unload; doing so repeatedly mars the bullets/cases, as they've got to be cycled through the chamber. Lately at end of day I've taken to carefully unloading chamber, and closing bolt on empty chamber and putting that one round back in magazine with the others. I'd prefer to fully unload for safety/legality reasons (need to check this), but as I said it's inconvenient.

6. If I see deer across field, I'll be leery of taking the shot that I might take with the .270. On the other hand... if it is too far for me to shoot with the 30-30, it is probably further than I should shoot, unless I've a perfectly steady rest and ideal conditions. I'll have to practice some 200yard shots with the 30-30.

Those are all the flies I can find on this rifle/cartridge. I still like it, it's beautiful, it hammers the deer and I got a great deal on it... just need to remember to take that safety off when in the tree or stalking!