We talking Normal Route? If you want a little bit of adventure, I'd say go with no guide. Plenty of other threads have people saying the same, so feel free to get a second or third opinion.
I climbed the mountain in February (2013). I was very happy about my choice to go it alone. I soloed the mountain. I got to go at my own pace and do precisely what I wanted to do. Normal route is really a very windy bunny slope and doesn't really require a guide. Sure it is helpful to have someone do everything for you and to have a group of "friends" to hang out with, but hanging out is not why I go to mountains. My only other previous experience above 5000 meters had been on Kilimanjaro, so it's not like I was some super experienced climber. I did no special training for the climb (unless golf counts).
If you can afford it I would go with either Grajales or Inka if you insist on a guided tour - but I would encourage you too book a private tour and skip the large groups. I'll tell you why later.
Inka and Grajales both had very large, swanky setups at Base Camp and provide a very good service. I used Inka for my mules and this got my privledges at their base camp (toilet, water). Buy one way mules. Buy half a mule on return. It's a great deal and I thank and recommend Inka for it! There are lots of a la carte options at base camp. I think you are better off just paying for them as you want or need them. 10 bucks to use the internet, or a a few bucks for a beer and pizza here and there is a Hell of a lot cheaper than shelling out 4k for the guided treatment or 1500 for the meal plan.
Ok here's my story if you are interested and why I don't think you should go in one of this big potluck groups:
My choice not to go on one of INKAs guided trips was a last minute decision. But I think it is the reason I summited the mountain.
I showed up at the hotel aconcagua, where I knew the Inka group would be staying and planned on starting the same day and sort of stalking them. A rockslide prevented all of us from getting to the mountain for about 10 days. At the hotel, I asked their guide if it was possible to get to any other mountains in the area and he said, "No, the roads are all closed" which turned out to be either a lie or false as I took a taxi to Cordon Del Plata without a hitch while they stayed at the hotel and drank Malbec.
(BTW Cerro Plata is a great warmup climb for Aconcagua at 6000 meters and in my opinion is much more interesting than sitting at Plaza de Mulas base camp doing acclimatization hikes. It has no paperwork, rangers, or logistics. So it's for purists, not yuppies)
When I finally got to BC at aconcagua a week later I found the yuppies in the INKA group again. They'd been on the mountain about five days and had been up to around 5000 meters, whereas I had already been up to 6000 meters on Cerro Plata and was used to sleeping at 5000 meters.
It was a Tuesday, and strong wind were forecasted for the next few days. Their guides kept them at base camp to wait out the wind with a summit day scheduled for Saturday. This is understandable, the wind can rip tents in half and if I were them I wouldn't want to risk destroyed tents as well as potentially freaking out your clients. However, this decision proved pretty fateful for their group. I went up to Nido that day (Tuesday) and spent two very windy days up at around 5500 meters acclimatizing. Yes, it was Windy but with perfect visibility and a ranger station adjacent to me I wasn't in any danger.
The INKA group showed up at Nido on Thursday after the worst of the wind had died down. That day I moved up to Camp Berlin at 5900 meters and stayed in a one of the three small wooden refuges there planning on spending another day at acclimatizing and waiting for the perfect summit window on Saturday.
On Friday, the Inka group moved up to Cholera camp (next to Berlin Camp), having only spent one day at Nido de Condores getting used to the altitude, which is a huge mistake in my opinion. Sunday was going to be Windy so it had to be Saturday or nothing at all.
On Saturday (summit day) they started early in the morning around 5 A.M. I thought about doing the same, but it was still really cold. I stayed in bed until the sun came up at 7:30. I left the hut finally at 9:30 when it was nice and toasty.
By the time I got to Independencia (6300) I had already passed most of their group most of whom had quit because the altitude, which their guides had not adequately prepared them for obliterated them long before getting anywhere near the real challenge of the Canaleta. I caught up to the few who made it to the summit just as they were finishing up their pictures around 2 P.M.. Of 19 climbers in their group only 3 had summitted despite it being a windless, warm, sunny day. It had taken them 9 hours to reach the summit and me only 5. This is only because I was better acclimated and their guides had not done their job getting them acclimated.
When I got back to the ski resort (las penitientes) they were all sitting there discussing the tip which some Americans had suggested 20 percent (800 bucks) was appropriate. It was pretty hillarious because most of the non-american climbers didn't think a 20 percent tip was warranted considering only 3 of them had gotten to the top. Although, I'm American I agree with the others that such a tip was rediculous. But yuppies are yuppies. The best was that the English in the group thought that someone should make a speech. However, of the three climbers who summited none spoke English very well. They were pretty much ready to fight one another over this gratuity and thanks issue (a pretty hillarious culture clash). For some reason some of the climbers seemed Hell bent on making sure that everyone tipped the same amount and that it was all presented to the guides at once in some grand socialist gesture of thanks to the guides (who im my opinion had cost them the summit). They couldnt believe that I summited in 5 hours. They thought I was some sort of Olympic Mountain Climber. Nope, just someone who had enough time to acclimatize. Silly yuppies.
In these big groups you are forced to work with the lowest common denominator. That can cost you the summit. Your guides, rightfully so, won't take any chances either with their equipment (tents) nor with potentially scaring the Hell out you by making you camp in 60 km per hour winds. You have to work on their schedule, and that schedule will be designed with safety and the happiness of the rest of the people in your party in mind, not with getting you, as an individual, to the summit. They have to run a business, and if you run out of time, you run out of time. The solo climber can wait until things improve.
If you are gonna shell out the money for a guide then shell out a little more and get a private guide for you and maybe 3 other similar climbers (preferably friends) so that you guys can have real input on how your climb goes.
