Everyone has their own preference, it depends on how you want to play. My take on the routes is as follows.
Spec Ops - SA - A good solo route overall, the stealth aspect makes many would-be attackers bugger off. Sleeping Gas Traps are very effective at stopping flak, but you need good sweepers. Health-Based lethals tend to die more easily though.
- Puppets - good if you just want to have fun. Dies easily, but you can bribe an army up easily enough if you try.
-Bunkers -THE solo route, bunkers with sentry turrets are very difficult to land on, and with plenty of Ninjas to flak your troops, makes them a tank. You won't be able to attack much unless you just mass flak though, as bunkers and sentry turrets are immobile.
Military - RPG - Very powerful anti-armor route. Not very good solo though as many folks will attack you just to kill your troops.
Harrier - not as good as RPG at killing armor, but better at running solo. Harriers are fragile but fairly strong and fast anti-armor. Rangers are very tough, target pure lethals, and do a fair bit of damage. F-117 is decent for killing flak.
Striker - Tougher than Harriers and RPG, they don't do as much damage and tend to be more expensive. It's not a bad solo route, Apaches target Lethals and Innocents (flak) which can be useful for stopping flak-attacks. Marines are pretty epic, being very hard to kill and doing decent damage for a very cheap price. Not a bad route for solo at all.
Fantasy - Vampires - Typically a good solo route. Vampires do a bit of armor damage, fire at the same time as SA, and are stealth. Makes for a decent route. Mummies are very tough, and do a little extra Armor damage before vamps. Werewolves are cheap and fairly tough for their price, having a bit of armor. Not a bad solo route.
Dragons - A powerful route used correctly. Their Sorcs targeting ALL and doing quite a bit of damage makes this route unlikely to be flakked or pommed. Dragons do a lot of damage, and the whole route tends to put off would-be attackers. Sirens are good for keeping TLs away. A good solo or allied route. Tends to die to robo.
Thug - Petrol - Petrol Bombers are very effective at killing if they fire. Early round they pretty much own the game until nanos come out. Later round, they do well combined with bikers to kill poms. They die easily though, and fire late. Jeeps are one of the toughest units in the game, having a massive amount of armor, and TL do a bit of armor damage and a bit of Health damage. They are effective at killing just about anything if you have enough of them. Terrorists are good for clearing out flak.
Attack dogs - Dogs are cheap lethal flak and will scare most folks off if you last-tick with a lot of them, the rest of the route is the same as above with jeeps being replaced by the rather useless unit, nutters.
Arsonists - Effective at blocking poms before they fire, you can essentially send an ETA 3 attack with gardeners, thiefs, and arsonists and steal land off of a pom.
Protestor - Political Masterminds - an often under rated route by newer folks as it doesn't really have lethals. This route excells at blocking other troops, particulaly flak and non-armor lethals. There isn't a lot out there that kills these well, and you will be more capable of keeping your own land. However, as a solo, be prepared to have everyone and their mother try to steal your land or bribe your troops. Decent solo route, very good for alliances. Hypnotists are a decent unit for bribing, I got the bribing award with these in just under a week.
Violent Demonstrators - I have never actually played this route. It has gurus to stopping land, and terrorist leaders for killing stuff. I'm not sure how good VD are at killing, I've seen them kill poms somewhat effectively.
Extremists - an extremely defensive route. Early round, the rebel is useful for hitting those pesky PB that think they can rule the world, with Extremists and Fanatics, you can scare off most attackers on your last-tick by doing massive amounts of damage. They only fire close range though. It takes a VERY active and VERY contactable person to play extremist effectively. Otherwise, everyone will just kill you off at range.
Robo - Shields - Shields are cheap and very high-armor lethal flak. Cyborg Gardeners are armored flak. This route excells at getting land in the right hands. Cybernetic Warriors are heavily armored and do a fair bit of damage, while Tyrant Drones are less armored but do more damage. They are the bread and butter of your lethals in any robo route. Not a terrible solo route, be prepared for people to regularly try to kill your troops though.
PA - Autos and Psychopathic Androids are cheap and armored. Autos are an early flak and hippy killer, can be used for lethal flak later. PA fire very early and does health damage, a decent health-hunter.
Nanos - The best robo-solo route in my opinion. You have Stun Bots and Nanobots here. Stun bots fire very late, are non-lethal disablers (as opposed to distractors) so they are targetted by even less than poms. This makes them good for sweeping up after the rest of your troops to save your land. Mass amounts of small droids with some stun bots to sweep will make you very difficult to steal from. Nanobots are very tough, with a fair amount of armor and health, they fire mid-range and close range, while replicating themselves for every troop they kill. People may only attack you at range though, recalling and resending until all your troops are dead.
All 3 robo routes have the same P-unit options. Scraps and T-Rex. Neither are really worth your money, but they are both fun to play with. You can use scraps to make gargantua (the single most powerful unit in the game available for players) which fire mid and close. It takes a lot of time and effort though. T-Rex are the 2nd most powerful, firing only close range, but you don't have to build them. A few million of these at close range should keep most folks away.
Well, thats my "slightly" still-asleep take on all the routes. Take this all with a grain of salt, I have played most routes, but some have been a while ago, and everyone's experience will differ based on their circumstances.
I almost always play solo.
