An AK74 can be a fine gun. There's all kinds of AKs of varying degrees of quality and value...and yes, many are mix/match rifles.
My own personal preference would be an AK47 (7.62x39). If I want a smaller/faster round (which the AK74 is), I'd strongly prefer (and advise) going with an AR15. It's a far better supported round state-side, with a wide variety of bullet options, magazines, accessories, etc. You can get into basic brand new, extremely accurate and reliable ARs for about $600-800 right now. That might not be the case in a few months.
Long story short: An AK74 can be just fine, but major preference to an AR15 or AK47.
Isn't this the handgun forum? AK "pistols" exist, but aren't terribly practical in my opinion.
"The Future is Unwritten"