MacOS – OS X upgrade on MacBook Pro mid 2010 trilemma

I'd like to have some feedback from those of you who have experience to share about upgrading OS X on MacBook Pro 15" (mid 2010 – MacBookPro6,2).

I'm running OS X 10.6.8 Snow Leopard, and I've never needed to upgrade because I use my mac only for software development on the java environment, so I've never needed to stay up to date and I don't even have Apple or Android devices to sync. So, just consider the main use I do of my Mac is about developing on the java platform (ad just for fun).

Now I need to move to Java 7 or maybe Java 8 and I need to upgrade Snow Leopard to one of its successors:

• Mountain Lion (10.7.3 at least)
• Maverick
• Yosemite

Here's my trilemma: which of the aforementioned OS would better fit my laptop's hardware? According to Apple's official site all of them have the same minimum requirements:

• 2 GB of RAM
• 8 GB free HD space

Here's an excerpt from the System Profiler running on my laptop (translated from Italian localization):

• Model name: MacBook Pro
• Model ID: MacBookPro6,2
• Processor name: Intel Core i5
• CPU speed: 2,4 GHz
• Number of CPUs: 1
• Number of cores: 2
• Cache L2 (per core): 256 KB
• Cache L3: 3 MB
• RAM: 4 GB

Please, don't point out the latter are free – I know – just focus on performance.

Personally, I don't feel like upgrading to Yosemite, but I'd rather move to Maverick. This is not based on figures, just on my gut feelings: I suspect that Yosemite may be too demanding about hardware configuration.

What do you think?