Well, sort of neither. My opinion anyway.
Anybody that's a reasonably good pilot can and should feel comfortable in flying any airplane (within reason) by the end of the first 100 hours (assuming a typical training program prior to getting in the plane).
This has almost nothing to do with being able to handle an airplane. It is all about the general all-around experience that someone brings to the cockpit as part of a team. How much exposure to weather. How much exposure to equipment malfunctions. How to prioritize when things get busy. How to work as a team. Understanding both your and your copilot's limitations and strengths and the best way to use that knowledge. General understanding of the capabilities and limitations of ATC. Understanding how ATC does what it does and how that impacts all portions of a flight. Having the experience to understand when you need to be planning alternative plans of action, and how to set the limits that trigger those plans. Implementing an alternative plan, including how you inform ATC, your co-pilot, and your company of what/why/when without getting overwhelmed. Understanding when it's time to cut extraneous factors from your to-do-right-now list, and how to prioritize those items....
Give me 5 minutes and I can double that list.
Experience is all about experience. So many things happen in every 1,000 hours of flying an airplane that each 1,000 hours adds to a pilots knowledge, understanding, and skill.
Very much so... even to the point of little things, like for instance, If you launch out of EWR off the 22's, and you are going to the north, what climb profile are you going to plan? or are you going to just blast out of there at max rate of climb? North dept's off the 22's means you are going to get stuck at 6000 feet until you are a good 20 miles north of EWR, so it's in your best interest to climb at 250kts at get north of the field asap.
On the other hand, If you are launching wrong direction off an outstation, then climb as fast as possible until you turn on route... etc. It's these little planning things that seem to matter more to the guys with lots of time.
If you're on the downwind, and can see that you are # 2, or 3,4 5 etc for the field, there is no reason to go past the field at 250 knots... slow up and let your spot come to you. (assuming nobody behind you etc) It's the "big" picture that the experience opens your eyes too... and lets you fly better, more efficiently, and more safely. There isn't much nicer than a crew member with you that really gets it, is ahead of the game, and is an extension of what you are doing. When both members are on the same page, think the same way, then it really works well, and it makes even the short 15 minute flight easy.
And, guys, I mean it about going out and having fun now. You really don't know how good you have it. Find a good student, and talk him/her into going on a fun trip. $100 hamburgers are great. If you are in the NE, fly up to alton bay for the presidents day pancake fly in on the ice runway. Bring a camera, and get some stories.