(Edit: HiveMindEmulator points out in a reply to this that WW already posted an improved IGG bot in the BM+X thread.)
Nothing exciting here: I simply added a rule to buy Province whenever possible. This improves on the IGG bot that is included with Geronimoo's simulator. It is a little stronger against BMU & Smithy and a lot stronger in a mirror.
Edit: I should probably explain why I made a post for such a boring bot. The reason is that I sometimes look at bots to find the "canonical" way to play one-card strategies, and for IGG the current bot seems to suggest that it's better to only buy duchies and not provinces, which is false.
Results are from "Accurate Simulation (10000 games)" and are given with 99% confidence intervals. "IGG" is the original IGG bot, and "IGG2" is the one that buys Province when it can afford it.
IGG vs BMU:
Win: 89.2% +/- 0.8%
Loss: 9.5% +/- 0.8%
Tie: 1.3% +/- 0.3%
IGG2 vs BMU:
Win: 93.6% +/- 0.6%
Loss: 5.9% +/- 0.6%
Tie: 0.5% +/- 0.2%
IGG vs Smithy:
Win: 73.6% +/- 1.1%
Loss: 24.3% +/- 1.1%
Tie: 2.1% +/- 0.4%
IGG2 vs Smithy:
Win: 84.2% +/- 0.9%
Loss: 14.4% +/- 0.9%
Tie: 1.4% +/- 0.3%
IGG2 vs IGG:
Win: 63.6% +/- 1.2%
Loss: 30.1% +/- 1.2%
Tie: 6.3% +/- 0.6%
IGG2 bot:
<player name="Ill-Gotten Gains Improved"
author="blueblimp"
description="Get all the Ill-Gotten Gains and Duchies to empty 3 piles. Grabbing Province whenever possible improves the bot.">
<type name="BigMoney"/>
<type name="UserCreated"/>
<type name="SingleCard"/>
<type name="TwoPlayer"/>
<type name="Province"/>
<type name="Bot"/>
<type name="Competitive"/>
<buy name="Province"/>
<buy name="Ill_Gotten_Gains"/>
<buy name="Duchy"/>
<buy name="Estate">
<condition>
<left type="gainsNeededToEndGame"/>
<operator type="smallerOrEqualThan" />
<right type="constant" attribute="2.0"/>
</condition>
</buy>
<buy name="Silver"/>
</player>
