Lords of War
The Lords of War slot is perhaps one of the things which has caused the most controversy in 40k in recent years, and caused a massive divide in the community over its allowance. Nevertheless, many places and kowtowing to GW's mandate that it is an expansion to the base rules, rather than simply an optional extra. With that in mind, it behooves us as players to examine the options presented to us by the book. The question of if you should bring a Lord of War comes down almost entirely to if your force is strong enough to gamble with ~3 victory points comfortably. Generally, we'll want to make sure to utilize a cheaper LoW option, so that it doesn't compromise our basic list constraints (don't downgrade tactical marines to scouts just to accommodate a super heavy), especially if that LoW doesn't bring any strength D weaponry. Strictly speaking, most everything produced for Apocalypse has been stamped for play as a Lord of War, but the only one actually contained within Escalation is the Thunderhawk Gunship. It plays similar to the Stormraven and really isn't worth examining beyond that understanding. There are three which warrant greater detail though: the Warhound, the Fellblade, and the Typhon.
I'll also note here briefly that if in your play area, you're having trouble coping with an opposing LoW, consider disregarding one of my basic marine principles: bring more troops. Push yourself to 4 troops at 1850 and play to the mission at hand. It may still be an uphill battle, but 5/6ths of all games are objectives based, and putting more models on the table that can capture objectives, as well as some models or units which are big threats to LoWs (Sternguard, Centurions Devs) will force target priority on your opponent. They can either kill the stuff which can kill their Lord, or they can scour your troops. Don't get discouraged and play through.
Warhound Titan - Great

Fellblade - Great
For a few points less, you can bring a Fellblade instead of the Warhound. Now, it's not nearly as impressive a piece in terms of fire output, but it's still very potent, and possibly more durable per point. It's got a whopping 12 hull points, and the primary cannon puts out three blasts of varying sizes in addition to the demolisher cannon that comes folded in. This earns a great without any strength D weapons because it still does an exceptional job with crowd control, while being tough, and cheap enough to still include an army with it. MCs will give it fits, but that's what support is for (grav weapons ahoy!). This option is also significantly easier on the pocketbook than the Warhound is, which is certainly something to consider.
Typhon Heavy Siege Tank - Great

Fortifications
After blitzing through the Lords of War, we come to the first of the new FoC options which came with 6th edition: Fortifications. This buyable terrain was the first major change that tournaments had to make to the BRB, mostly because the rulebook treats it exactly as that: terrain. And with good reason: several of the structures have no guns or ability to be fired upon (they are actually terrain). So, when should your marines spend some of their points on terrain rather than their unique killy options? That's a tricky question, especially considering that generally, we don't want to give our opponent any more cover saves than we have to. In this regard, consider fortifications extremely carefully.
Aegis Defense Line - Great
Honored Imperium - Okay
The Honored Imperium is the epitome of the brief descriptor above. It is literally terrain. And that's why it's only labelled as okay. The points cost is low, but the benefit to your army in terms of cover generated is pretty low. No, most of why you'd consider these bits of rubble is the modifications they give to leadership. Stubborn really isn't the best rule, but it (or the fearless provided by the statuary) can definitely help you save some points here and there in costs of sergeants. It's meta dependent but far from the worst option available to us.
Firestorm Redoubt - Great

Vengeance Weapons Batteries - Great
In the same vein as the firestorm redoubt, there's vengeance weapons batteries. These bear similar firepower to the redoubt, but offer decentralization (they're a single or pair of turrets). This is for better and for worse. It allows you to set up kill lanes, but at the cost of the bunker. These do lack the special rules of the redoubt as well, making it a much more tempting platform for a battle cannon (and wow is it a cheap platform!). If you're looking for the battle cannon, definitely consider these as an out, rather than the redoubt.
ForgeWorld Goodies
Here we find ourselves. The last of our "native" codex entries. Everything from here out is allies, inquisitions, lists and tactics. And this is the furthest fringe of our definition of native codex contents. Up until now (Lords of War notwithstanding), every model and all the rules for them have been produced by GW, meaning their legality wasn't really a question. That's not the case with ForgeWorld entries though. Over the last calendar year, we've seen a much bigger push for FW to become legal, but many places still abide by the notion that they're unofficial and therefore require your opponent's permission to use. That said, I'm going to write this piece of my review under the assumption that these models are legal and considered part of the SM codex. Here then is our final chapter.
Contemptor Pattern Dreadnought - Better than Okay, not quite Great

Lucius Pattern Dreadnought Drop Pod - Better than Okay, not quite Great
Hot on the heels of the contemptor comes the dreadnought drop pod. The most recent rebalancing follows the current GW trend of allowing your opponent a full turn of shooting against something before it can assault, meaning that this fast attack choice is certainly less powerful than in the past. That said, it does still provide a 3 HP AV 12 shrouded cocoon for your dread to assault out of next turn. The problem with this model is the tag in dollars, rather than points, clocking in at nearly $100. Ouch.
Relic Predator - Great
Not unlike the contemptor, the relic predator is a slight tweaking and retooling of a codex entry. It's still every bit as points effective as the native one, whilst supporting a dazzling array of exotic and otherwise enticing unique options, including lots and lots of fire, or a conversion beamer. If you've got the coin, give it a shot, but likewise, you're not missing too much if you don't happen to have one.
Conclusion
Well then ladies and gentlemen, there we have it. We've examined every unit available to us. That's all there is, there isn't any more. And quite frankly, every slot has something worth including. The fast attack is certainly the weakest slot (due in no small part to troop bikes), but even it includes some choices worth considering. But we're not quite to that point yet. Next, we'll look at available allies options, so as to be better equipped in two weeks when we start to examine some basic principles of list construction. Hope to see you here!