I don't trade stocks with Sierra but use the program and I think the general consensus is it's a far better package than Ninja. The only problem with Sierra is it has so many bells/whistles it can take time to understand how it all works.
A scanner is more useful than ninja or Sierra. In IB TWS mosaic you can link the scanner to the chart and execute on the chart. www.trade-ideas.com www.scanz.com
Too expensive and i can see on the tws scanner which stocks are moving (% change since open). I hate TWS charts.
If you want ATM with ninja, you have to pay almost $1000 for the software. You can't place an order with preset target and stops without paying.
I´m not on a budget, because i´m using tradingview and sierra but have no need for those scanners, because tradingview and tws have their own. I don´t need scanz or trade-ideas to get premarket gappers. Scanz or trade-ideas maybe good for finding momo stocks, which have a big move after market opens, but you also can find them with tradingview or tws. But this was not my topic. It was about order entry with third party frontends.
I don't think SC has ever had a good relationship with IB. In fact, on SC's support board, SC has absolutely savaged IB on a number of occasions, as they have with other business entities where they are experiencing interface problems they feel are not SC's fault. Since they haven't pulled this post down from their board, I assume SC still feels the same way about IB. You might want to read through it before making a final decision: https://www.sierrachart.com/SupportBoard.php?ThreadID=48856