Buy side OMS software suggestions

we always have a choice to either develop our own OMS (order management system) or buy off the shelf. Both has it's pros and cons. Due to limited resources and limits time to go live, lot of people decide to buy off the shelf products in the beginning.

At an early stages, I am looking to buy an off the shelf product as well. As I start my research on google for the available products, I was amazed to see so many products available and all off them offer various features. Some supports very low frequency trading to limited product types etc. I couldn't find a one place comparison of these products to help me select one that will match my needs. I am mainly interested in a connectivity solution to brokers and not interested in a GUI platform. We will develop our own platform with automated trading capabilities. We need a product which has connectivity to various brokers, support for various products etc and a good API with sufficient call backs for order management.
My requirements are as below:
1. Multi asset support (Equities, futures, FX, commodities)
2. DMA and Algo support
3. Coverage of global markets (exchanges, ECNs)
4. coverage of brokers (lead brokers in each region, country etc)
5. 24/7 support and support for adding new features/products/markets etc
6. cost
Could you share your experiences with products, or you think is a good product or some comparison?

I am looking at Fidessa, Eze Software, FlexONE as of now.