This is a common question, what is a good entry level HF rig. And one would think the answer would be pretty easy, rig A, B, or C. However it is really a quite convoluted issue.
The best bang for the buck is probably going to be a few year old, one or two generation back, radio that was not entry level for its time. Unfortunately that can be a problem, are you getting a radio that has gone through 4 people because no one could figure out what was wrong with it? Are you getting a radio that someone else upgraded from because it was a dud? Or are you getting a well taken care of rig that works perfectly well but the owner just upgraded and no longer needs that particular rig?
The new user, typical of who might be looking for such a rig, is most often poorly equipped to make educated guesses as to the probable scenario behind the radio based on quick assessment at hamfest or similar situations. And so they are the more likely to end up with a poor performing / marginally broken problem child radio that someone else wanted to get rid of. Because of this I generally suggest to such a person that unless you have an Elmar or someone you trust to help you evaluate a radio before you purchase it avoid the used radio market until you have a little experience. Buy new, the chances of getting burned are much lower.
Then the field becomes much more narrow. Typically radios ranging from $530 to $1000 are in the entry class. Instead of looking for a radio with the most features look for one with feature sets that might apply to you, think about your use. Do you want an all in one radio, with 160 m to 70 cm? This is very tempting, but at the entry level this also means no dual band RX, so if you are working 2 meters you cannot also monitor 10 meters. This limitation is why I generally suggest the new user NOT get an all-in-one rig like the Icom IC-706, Icom IC-7000, or Yaesu FT897. Most newer users only use FM on 2m and 70cm, and a nice dual band can be had new for a couple hundred bucks, so I suggest getting an HF rig (HF+6m) and a separate VHF/UHF rig.
When people start talking about entry level radios of this type they say things like Rig X is OK, but lacks features or does not have the adjustability I desire. True, but that is typical of most entry level rigs. Sometimes people unconsciously compare them to radios in the next price range up. Be sure to compare apples to apples in feature sets and cost range.
The IC-718 is a good bare bones entry rig. Very low cost but very limited feature set. The Alinco DXSR8T is even lower cost and more bare bones. Between the two I prefer the 718, keep in mind neither radios have 6 meters. All other new rigs step up in price from these two, but also step up in features. Are you going to want an antenna tuner? I bet you will. So now you get up into the Yaesu FT-450 and Icom TS480SAT range of price. The FT-897 is in the same price range, but lacks a tuner and gets back to that whole all-in-one radio question.
And this is where I normally place a mark. My suggestion for the best entry level rig on the market today is the Kenwood TS-480SAT (not the 480HX, the extra power is not worth the loss of the tuner). Having used it side by side with the FT-450 I find the 480SAT RX to be a little bit better. I also like the packaging of the radio (remote head) and the display a little more in the Kenwood. For about $200 more than the IC-718 you get a lot more radio. This $200 would be about the cost of adding an external antenna tuner to the 718, but the 718 would still not be as capable a radio as the FT-450 or TS-480SAT.
As if that was not confusing enough, consider what antenna you plan on using. Remember I talked about internal antenna tuners and said that was a desirable feature? If you are forced to use a really substandard antenna an internal antenna tuner might not be able to tune the antenna. Typically internals are not as capable as externals, often being limited to fixing a 3:1 or less SWR. In such a case (poor antenna) even if your radio has an internal tuner you might end up needing an external tuner. I still think the TS-480SAT is a good choice, the receiver is very good.
In the end you have to look at your entire situation, think about the system you will be building (antennas, bands of interest, etc), not just the radio you want.
T!