Fan of the series or new to the series its worth the purchase for your collection. And playing both games on the go
Both games still play well and nothing has really changed from its gameplay, if you've played both titles back on the PlayStation 2 nothing much has changed, but do note that you'll be using the left analog stick to move and holding R button and Square to fire your weapon. Instead of using the shoulder buttons to select back and forth weapons and items, on the PS Vita you are using the touch screen to select weapons and items like you would do on a DS handheld or a touch screen mobile phone.
In Metal Gear Solid 3 you can use the touch screen to patch up Snake if he's badly injured during gameplay or getting rid of gunshot wounds. Apart from that nothing hasn't really changed much on its gameplay it is trying to be more touch screen related for the handheld version.
Yet both games do look impressive when they are in HD both cutscenes look very well detailed to look at on your PS Vita. The voice acting is still the best as it was over 10 years ago and the soundtrack makes a great a touch when you're playing both games when you are out and about either on a bus to work or hanging out with your friends. If you have a PlayStation 3 you can transfer both saves back and forth to your console and to your PS Vita, the only downside to the Vita version of Metal Gear Solid HD Collection is that it does not contain Metal Gear Solid Peace Walker in the collection.
Not only that the HD Collection also contains both MSX titles Metal Gear and Metal Gear 2 which makes another good feature being added into the collection also including the VR missions as well. Trying to obtain all trophies will be a challenge for trophy collectors, as a Metal Gear Solid fan I would recommend the HD Collection if you have played the games before or new to the series it's worth the purchase if you want two of the best stealth action games that made the series is memorable and great for what it is.