While Orc Boyz received a one point increase for no obvious reason, the Savage Orcs retained the same point cost as in the last book. Add to that the fact that additional handweapons cost them a point less than they used to, combined with frenzy no longer meaning your unit will automatically charge anything in range (needing only to pass a leadership test to restain) and suddenly Savage Orcs are looking more and more like the proverbial steal of the new Orcs and Goblins book. Such coincidence that this unexpected turn came right as new Savage Orc models were planned for release!
On a more serious note though, Savage Orcs will no doubt turn out to be the no-brainer choice for our core points, once we've had our fill of goblins and fast cavalry, in many respects replacing the Orc Boyz. With each model dishing out three S4 attacks on the charge, Savage Orcs will be able to tear through similarly priced enemy core troops. Although they lose out on the 5+ armor save of the Orc Boyz, with toughness 4 the attacks that are strong enough to worry them will probably go through both the light armor and your shield easily, meaning the Boyz would be depending on their parry save in most instances anyway. Bear in mind then that the warpaint save of the Savage Orcs will also work against shooting, artillery, impact hits and stomps (all of which the parry save will not) and it is clear which Orcs should result in the most competitive army lists (not to mention that almost everyone loves the idea of Savage Orcs in the first place).
With such a high amount of attacks for a regular rank and file orc, combined with a far less harsh animosity table, the need for a Black Orc or other fighting character to lead them is mostly gone, although it could be a good idea to deploy one with them for the first turn to make sure they're moving forward initially. Savage Orcs will also be one of the prime targets for your spells so it is well worth keeping your Shamans nearby, if not leading the unit. Spells like 'Ere We Go!, Itchy Stabbin' and even Gift of the Spider God will greatly increase the effectiveness of your Savage Orcs in combat.
Bear in mind, however, that frenzied units will still have to pursue and even overrun at all times whenever they defeat enemies in combat. One failed leadership could mean your Savage Orcs are running after some annoying Harpies, putting them way out of position and in range of a flank charge from the enemy. Remember that if your Savage Orcs lose combat even once, they will lose their frenzy and turn a lot less fearsome for enemies to handle. Bring plenty of small support units to prevent your Savage Orcs from running after every single bait offered, or bring so many Savage units that it won't matter if one of them runs off to the side.
Big 'Uns: For one point less than a Black Orc without a shield, you get a frenzied Orc that actually dishes out even more attacks than the dual wielding Black Orc would, at the same strength. The Savage Orcs will be less flexible, a lot more prone to charging things that you'd rather not and end up in poor positions, but if handled well turns into one of the more fearsome core choices out there. Saurus Warriors, Longbeards and Bloodletters are all slightly more expensive in points but will have a hard time against a mob of Savage Orc Big 'Uns. As far as Orcs go, this unit will most likely be quite expensive and the prime target for spells and shooting. Which is why these Big 'Uns will be the only unit worthy of having a Savage Orc Shaman join them, carrying the Lucky Shrunken Head to increase their warpaint save to 5+. Add some magic resistance to the unit as well, and your Savage Orcs will be able to withstand Hellcannons, Grudge Throwers and enemy direct damage spells better than most others would, without the fear of them running away from it.
Unit size: Depends a lot on what you want them to do, and how big of a target you want them to become. Both regular Savage Orcs and Big 'Uns can be fielded in about the same sizes, ranging from 14-21 for a hard hitting flanking unit that can hold its own against lesser foes, to 24-40 for an army center piece that will go up against the best of what the enemy can muster. Deploy them as wide as you can fit into combat, even Horde them if you can to maximise the amount of attacks they dish out.
Equipment: While additional handweapon dropped in price, the shields and spears did not. Seeing as how you get the same amount of attacks out of fewer models with two weapons instead of spears, with the spears being more of a defensive options for units that aren't, say, frenzied maniacs that only want to charge in early, bash 'eads and continue on, there is little question how you should equip them. Double choppa, all the way!
Command Options: The Standard Bearer helps you win combat by more, and the Musician prevents you from losing frenzy in case of a combat tie, making both upgrades well worth getting. The Boss provides 4 S4 attacks at WS4 and will cost you even less than two Savage Orcs in total, so is definitely a good buy as well, with or without characters leading the unit. For Big 'Uns, and without characters, you may want to drop the Boss and get yet another orc into the unit instead.
Big Stabba: A slightly strange item with an obvious use that will rarely, if ever occur. It deals D3 S5 impact hits which is fine if you want to maximise the damage you deal on the charge, although slightly pricey. It also gets the multiple wounds (D3) rule against large targets, but the problem is that a ranked up unit with M4, with an obvious monster hunter weapon, will have such trouble ever catching said monster, who in most cases is a lot quicker and have the ability to pivot during its movement. Now, if Savage Orcs or their Big 'Uns were able to bring magic banners to the field, it might have been worth giving them the Banner of Eternal Flame and go stab Hydras, but since they cannot, you're probably better off avoiding the monsters and getting a few more bodies instead of the stabba. Monsters are one of few units able to inflict so much pain to the Savage Orcs without taking that much in return, that they will most likely break their frenzy and severely cripple them for the remaining rounds, stabba or no stabba.