Now for the comparison of the two platforms. I came to like the IB TWS, especially the more that I used it. First the features that I miss.
Note: Because I trade only futures, there are a number of features in TWS that I did not use and will not address them here.
TWS OCA: With this feature, you can quickly enter your position, then put in your goal and stop with a group identifier. You can then have a level of comfort in walking away from the screen. For example when long, my OCA group would have a sell order entered as a goal, a stop-limit as an intended maximum risk and a trailing-stop to lock in some profit on the way up. While a liked the concept a lot, I rarely used it, simply because I am in front of the screen all day anyway. X_Trader does not have a One-Cancels-Another or One-Cancels-All feature, except as an add-on module to X_Trader Pro. X_Trader Pro cost $1450 per month. According to Mark Oryhon at VF, there are only just over 40 traders using X_Trader Pro in the entire country.
Trailing stops: Yes in IB TWS, no in X_Trader. Again, I would normally trail my stop manually during the trading day, so while I like the concept, I won't actually miss this feature.
Automated Stop Values: One of the cool things you can do in TWS is set up a different stop value for each contract. For example, you can set an ES stop of 1.5 while your ZB stop is 0.125. Then, when doing a bracket order, or a stop attached to the entry order, it will automatically start from that value. No similar feature in X_Trader.
Third party plug ins: Some traders love the plug-in platforms that work with TWS, like button-trader, auto-trader, bracket-trader, etc. I personally didn't use them; however, I did use Medved Quotetracker as a backup charting program. As far as I can tell, no similar plug-ins are available presently for X_Trader.
Now for why I like X_Trader. X_Trader includes a simplified order entry method called Market Depth Trader. (This is in addition to the more traditional Market Explorer where you can enter your orders.)
Market Depth Trader (MDT) becomes addictive once you use it. The speed of execution it touted to be the fastest of any platform, and after using it, I would not dispute this. In MDT, the bid\ask depth are oriented vertically. When prices are going up, they climb up your screen, and when going down, they drop on your screen. Recentering is either automatic or manual, your choice. I keep the CME currencies (which I trade rarely) on auto, and both ES & NQ on manual, using the mouse wheel to recenter it.
While other platforms may show you the last size, MDT shows first last, then cumulative last size. For example, if there is a five lot taken at the offer, the 5 shows with a green highlight. If followed by a 250, then a 1 lot in rapid succession, instead of showing 1, it shows 256, now with a white background. Others on ET have described this as the "Eating" phenomena and I can't imagine it being displayed any better than how it is done in MDT.
Additionally, MDT records the volume at each tick while it is open. It can be displayed either numerically or graphically. In effect, MDT automatically builds a volume profile, which is cool.
With TWS. the order type can be changed to stop before you click "Transmit." With MDT, you click Stop or Stop Limit, which changes your cursor shape and color, then click the buy or sell price on the vertical grid. MDT also has a "Trade Out" button. Click this, and you will instantly be flat by exiting at the market.
If you trade by the POP imperative, "Be Swift!" then MDT is for you.
In summary, for the day trader in front of the screen all day using frequent rapid entry and exit, MDT gets the nod. If you are a position trader and frequently not watching the market during the trading day, IB TWS wins hands down.