I haven't used Multicharts much, but it is EasyLanguage compatible. And they are set up up with IB already. All software has some bugs, so I couldn't tell you which is better in that regard. My TS platform has crashed 3 times in the last 2 or 3 months. I lost thousand$ each time. It was due to the high traffic in FNM & FRE, which I was also trading.
Also NinjaTrader is a good program that you can try for free with a sim account. NinjaTrader doesn't use EasyLanguage however.
I have an account with TS. I haven't tried IB as yet. "Technical Analysis of Stocks and Commodities" mag rates IB #1 broker, and TS as #1 platform. I may give IB and Multicharts a try myself. TS has a very large support community however, when compared to Multicharts.