So glad to hear that you've got your visa. I've flown through Gatwick several times and never had any problems, especially now that I have my visa.
Your first time going through with the visa will have a few more questions than subsequent entries, but it should be nothing compared to entering as a visitor. Is your SO travelling with you? Mine came through the line with me but it's not a problem if you enter alone (as long as your SO is already in the UK). I just told the officer that it was my first time entering on the visa. He checked it over, took my fingerprints (might have taken a photo, I can't remember), asked me if we were still married, stamped my visa, and sent me on my way.
Every entry after has been very simple. I don't have a BRP so I just say that I have a visa on my landing card. Sometimes they ask me what I do in the UK, if I am still married to my husband, etc. The last entry (Saturday evening), the only question was about the weather. Just remember that you've done the hard part already. You have the visa, it should be smooth sailing from here!