I just switched to DAS with TDA. I was with IB before. So far, I haven't noticed any major problems with fills. I have had a couple instances of bad slippage, but might have happened anyway regardless of the broker because I got stopped on a breakout. I am trading small size and doing lots of scalps, so the savings in commissions is definitely worth it. When I start increasing my trade size and profits, I will probably switch back to IB.
In my first couple weeks, these are the differences I noticed:
Need to change all my hotkeys to LIMIT and MARKET instead of SMRTL and SMRTM. No problem. Otherwise, it was really easy to switch from DAS IB to DAS TDA
It seems TDA will not allow me to close my position or close part of my position if I have a stop in place. I don't like this because I like to partial and then edit my stop after. Keeping the old stop keeps the little order marker on my the chart showing me visually where my stop was and I can click on my order and just replace my share quantity without redoing the stop. This is not a huge issue, but it is more work for me. I think TDA might be trying to protect people from accidentally forgetting they have a stop order and then get filled the opposite direction without knowing. Personally, I like that IB gives you the freedom to do anything you want even if it might not make sense for most people.
When I click to buy/sell, there is a delay in DAS showing my order in the platform...less than one second, but for those milliseconds I wonder if I was filled and what price I was filled. I think it's just the delay in the data showing the platform and not the actual price filled. So for example, if I was going long, I hit buy...the price keeps moving up and after a slight delay I see the trade triangle where I was filled and it is usually better than where the price is currently trading. The delay is a little annoying since I like quick scalps, but it looks like I get filled where I expected.
TD free commissions does not apply to every ticker or instrument. Honestly, I haven't figured out which stocks have commission or not, maybe the OTC ones (?). I will research this later since I just got started here.
There were also some names I can trade on IB, but not on DAS TD, like JUVAF. Again, I am not sure why (not short locate problem because I was long). Perhaps it was foreign - I don't know.
Hope this helps!