Yeah, I have a garantia for a two year lease. In fact, the biggest pain in the ass of moving into a two year contract is the garantia itself. You have to evaluate your needs and think about whether or not it's worth it.
I understand Ceviche completely. I don't remember if he said he was single or not before, but if he is, I understand completely the desire to stay in a tourist rental. Even with just a partner would make sense to me as well, although when we start talking kids (my situation, we now have three living with us) the need for space makes renting temporary more unlikely. The bigger a temporary apartment, the more expensive the rent (almost seems to be scaled logarithmically! Although as well, the more likely that apartment would be available for longer temporary rental as well), over and above what the price would be for a 2 year contract.
I had lived here for about a year and a half, and one of the expats I had made friends with had rented an apartment on a two year contract by paying the entire lease up front (he didn't have a garantia). He was called back to the States by his job before his lease ended and I was lucky enough to pick up his apartment and pay him the rent (the owner allowed us to sublet, which I found out later through experience was a minor miracle in and of itself). I had the place for a year. I realized that I didn't ever want to go back to temporary apartments. At that time, it was just my wife and I, but I had bought a small desk (hard to do serious work at home for a long time set up on the kitchen table) and was having to move that with me as well, every temporary lease-end.
In those days (2007), tourist rentals were a lot harder to come by on any kind of long term basis and I hadn't made many local contacts yet. I must have moved 11 times that first year and a half - I remember the longest rental contract I could get at the time was three months and I felt like I was in heaven on that one, not having to pack up my clothes the next month when someone else was slated to occupy the apartment I was in. Temporary leases were mostly full a good year in advance, at least in the class of apartment I wanted.
The market's changed quite a bit. Not nearly as many tourists as there were - I'm not looking at government figures, but I know two different guys who run temporary rental management businesses and although they are keeping busy enough, it's nothing like before. As a result, I think it's easier now to get a longer term temporary rental. But as you are experiencing, the prices are significantly different, which was another reason I wanted to move.
I was bitching a little about moving costs and all, but that's a relatively minor thing. Mostly I was just mentioning it because the OP who was looking for advice about the lease needed to think about that if they were going to vacate their current apartment for lack of heating. My last move, about 5 blocks, cost me on the order of $500 USD (not counting the new deposits for the new apartment, just the moving costs). Truly, the movers moved us in one day, did a helluva job (anyone want references, these guys are great) and I was very pleased.
But the garantia is the pain for me. I don't own property here and no one in our family does either. However, we've made enough contacts over the years that we have a friend whose parents sold us their garantia. It was even from Mar del Plata, which is not very usual that an owner will except something outside of Cap Fed as garantia for a Cap Fed apartment. Buying the garantia cost one month's rent.
Furniture can be very expensive here for anything that is really worthwhile. I got lucky - that first guy whose lease I picked up also sold me his furniture at a huge discount. I had made a good start with that. Over the years as I've lived and moved and increased my immediate family, I've accumulated things.
You just have to figure out if you want to go to that length or not. Personally, I had no real choice and am quite happy. I have no plans to leave Buenos Aires any time in the immediate or medium-range future. Even considering getting citizenship.
BTW, a little comment about temporary leases. The rental laws here are quite specific and are extremely beneficial to the renter in many ways (mostly having to do with occupying the property). A temporary rental doesn't have nearly the renter's rights that a 2 year contract has, which is why there two different contracts. With temporary contracts it's a lot easier to get the tenant out if they are not paying rent (although there are extenuating circumstances when kids are involved, for example). With a 2 year lease it's almost impossible to get renters out if they are not paying rent, for at least two years or more of court action. That's why the garantia is needed - the idea is to give the renter enough of a motivation to pay and/or move out (particularly at the end of a lease) or the owner of the apartment that was put up for garantia stands to lose his/her apartment.
But what many people, owners included, don't understand is that by law there is a limit on how long a temporary contract is valid. The maximum temporary rental contract is 6 months, and I believe it may be allowed to renew one time for another 6 months (can't remember where the actual limit is). But once you pass that limit, whether or not you have a temporary contract, the contract itself reverts to the standard long term 2 year lease. I mention that because this is another thing that often prevents owners who understand the law from renting temporary for more than 6 months. Some think just renewing the contract every 6 months keeps them safe, but it ain't so.