And here - as you would expect - is the opposing opinion; I've often been aboard, though never sailed on a Monsun, but my wife & I owned a Vega for almost ten years and sailed it UK to and around the
Mediterranean,
living aboard for 6/7 months each year and over wintering a couple of times too.
You say the Monsun will cost you $15,000 more than a Vega? that alone sounds a lot, but when you describe it as 'more than double the
price of a Vega' it sounds even worse; in the UK at least, you can buy a very good, re-engined and well maintained Vega for far less than US$15,000.
For boats of that era I doubt that you can find a boat of that size with more
interior space than a Vega and with both of us being under 5'9"/1.70m tall, the headroom's 'full-height' too; the demountable
interior table adding to the feeling of spaciousness. Yes, if you've been cabined-up down below for a week of cold, wet,
winter weather the Vega feels clostraphobic, but I've often done the same on our 35 footer and that's not significantly better. For the most part we 'live' in our cockpits and there it makes no difference if you're aboard a 27' or 47' boat; having said that, the Vegs's got a great/big
cockpit for its size too I've often slept up there, which I suspect the Monsun's seating may not allow so comfortably?
Passage times won't be much difference as the Vega - as you've already guessed - will perform better in light winds and whilst it's 5'/1.5m shorter overall than the Monsun, its waterline length is only 1'/30cm less. That 5'/1.5m length and a 1'/30cm saving on
draft will also provide you with a much better choice of harbours and more especially
anchorages.
The standard diesel/water
tanks on the Vega are not great for extended cruises (40/70 litres) but we found ample space - huge
cockpit lockers - to increase
water capacity to 190 litres and
fuel to 50 litres, along with a another 60 litres of fuel in cans, a
holding tank and a built in fridge; the Vega has unbelievable
storage space!
The one area that I'd probably choose the Monsun over the Vega would be in big and steep beam/head seas, whilst very strong, the Vega's a light boat and we found that though it would point close to the
wind, in those type of seas the bow got knocked-off and we made too much leeway - often motorsailed to obviate - and I suspect the Monsun would do better. That said, we made some long passages including Biscay in our Vega and to be honest, I spent most of our
passage across the Atlantic wishing that i still had the Vega (the winds were too often light).
A final consideration, particularly as you say you're 'no super-experienced' in favour of the Vega is the Owners club/group/family, with more than 3500 Vegas built the club is huge and very supportive; there's not a problem you can have on a Vega that someone's not had before you and won't be happy to tell you how to overcome, similarly there is always someone who knows where to get whatever part you need.
I wouldn't advise against the Monsun, it's a fantastic boat and I'd choose it over the Vega if I was going to go through
Panama and across the Pacific - though the Vega would still suffice - but otherwise, I'd save that $15,000 and maybe that will allow you to go full time a year earlier?