Uh oh. Someone asked me for my opinion! Such a dangerous thing to do.

I don't really like ratings, but some people seem to identify with them, so I'm going to grade the add-on as a B-. However, let's hope you continue reading to see why this grade was given.
Right off the bat, I loved Hearthfire because it allowed me a house near Riverwood, a location I've loved in the game since playing it. However, as time marched on, it soon became apparent the "be careful what you wish for..." curse set in, because the location started to become more of a problem than a benefit.
For playability, there's only one useful house in the entire game, and that's Heljarchen Hall, which sits right behind Whiterun. When it comes to the necessity of storing items to sell later, there simply is no better location. Lakeview Manor does get better once the investment perk is opened and the Riverwood Trader gets the 10k gold, but until this, HH should be the first house most people build if they're still playing the game and want something useful. It's not unusual most players will eventually build all three, so there's no rush for the other two.
The other surprise the DLC threw at us was the sheer number of iron ingots the house demanded in exchange for the nails, fittings, and hinges required for construction. My goodness, my paws are barren of fur with all the mining I've been doing in order to shave costs. People who want an immediate house will be paying top dollar to get it. Paying for sawn logs, rather than doing it themselves, runs 200g for 20 logs. Iron ingot and ore, as well as corundum, a few others for the tables, glass, straw, and goat horns gets expensive quickly. 5000g? LOL. That'll be the least expense paid once it's all said and done.
The layout of the house is canned, meaning we only get 1 of 3 options per 3 sides of the house, which was extremely disappointing, especially when it's discovered those options are not interchangeable. For example, you can't have a kitchen in your house if you've chosen the trophy room, because the kitchen can only be added to the east side of the house. Not sure why this was done this way, but it was disappointing.
The cellar addition was a surprise, but quickly turned into a chore as it's a zone. Anytime one enters or leaves the cellar, it's a load screen. And speaking of load screens, HF increases them any time one enters the "Skyrim" zone, regardless where you are in the game. My exits out of the cities take a few more seconds than they used to, and exiting the house makes it really noticeable as well.
Hearthfire is a nice DLC, and for the price, it's also reasonable. It offers a small "defend your house" game mechanic, though I've not seen this much (2 bandit attacks and a giant attack, and that's with all 3 houses built). I'm guessing the completion of the Horn's return in the MQ is required if one wants dragon attacks.
You're friend is correct when he said it was "alright". If you really want to enjoy HF, I would recommend you really take the time to build your house, rather than do what I did and rush to build it just to see it. Once I did this, the luster quickly dulled. It didn't take long for me to buy Breezehome anyway and store my gear there because the locations of the houses weren't making playability worthwhile.
Windstad Manor is, in my opinion, the worse house in the game. I mean, it
really shows why there's an abandoned shack next door.
