I play without barbs. It's the only way of being competetive, especially on Marathon. One can skip all early units but 1 Warrior for the capital, one can skip BW / Archery / AH... The only advantage of playing with barbs, is that AI also expands slower, but that advantage is morely minor, because AI defends it's cities usually with or without barbs.
If an AI builds the GW next to you and you play with Barbs on Marathon, you can basically quit the game already.
The game is btw. making me suffer too. I don't know why, but maintenance costs are like crazy. I rexed to 7 cities, took over De Gaulle and settled 2 more on the land that was still left, bringing me up to 20 cities. Some are costing 15 GPT without a Courthouse, I have a deficit of 200+ GPT and could not even afford 10% of research without running a deficit.
'til now, I could fuel that deficit by selling techs to the AIs, but that time is over, because I wanna take over the AIs, so I have to stop trading to them, or they'll have better units than I want them to have. 2 AIs are also researching like crazy, with doing 500+ GNP at 300 BC, one has the GLH and the other one a shrine from a 50% world religion. Also bribing is almost impossible with the buddhist love-fiest that's going on and because of the last, the AIs are trading like crazy, creating an insane overall tech-pace, at least for some. Best AI will probably reach Cuirrassiers 'til 1 AD, while the few AIs that got left behind don't even have Longbows yet.
Fortunately, one of those sits next to me

.
Still, I have to go to war with Trebs + Maces, because I see no way of reaching Rifling or Steel with Liberalism, and standard research would take ages. At least I'm probably soon gonna have my first Golden Age thx to the Taj Mahal, which I currently chop with running Serfdom.
Brennus was definately a good choice, loving SPI because of AP-Temples and the possibility to even run Civics like that, but also because it allows me to easily switch between OR, Theocracy and Caste and Pacifism.
Hoping you'll post some ingame reports too

. I'm especially interested in the one of
WastinTime . He probably got Oracle, which in my game went at 2300 BC, and he probably got a lot of Workers from abusing an AI.
Of course, I'm very interested in the reports of all others too.