If have both Blackmagic and AJA products in our facility. I’ve grown to love the tech support of AJA. For Blackmagic, it’s been almost non-existant (but I still have their cards that I got for cheep off ebay!)
You really need to determine what connections you need. Do you need to digitize component video? Do you really need HDSDI for your clients? What type of video monitor will you be using and how will it connect to the card? How will you be monitoring the audio, analog or digital?
From the sound of it, the Kona LH might be a great fit for you, but you really need to go through your whole workflow to make that decision.
Feel free to ask some more questions if you want.
-Russ