It does sound like the cheapest Alpha is a little too limited to allow me much forward use as games continue to bloat in size. I'll have to think on getting the mid range.
As a general rule if you're not going to be upgrading your computer yourself (and while one apparently can upgrade the Alpha without voiding the warranty the lack of space makes it difficult even if one does have the knowledge to do so) I'd always suggest getting at least a mid-tier model just to give you some level of future-proofing.
At the same time that's very much a general rule but not a universal one. There aren't that many AAA games (which tend to be the most system intensive) that are PC exclusives these days with most being multi-platform and many PC ports either being buggy or not taking advantage of the additional power a PC has. If the PC exclusive games you're interested in aren't monsters that demand a high level rig then you have to ask yourself whether slightly prettier graphics and/or a slightly better framerate for the couple of games you're going to play on it are worth the extra expense in getting a better system.
What I would suggest is if XCOM 2 is your main reason for getting the Alpha then hold-off on buying it at least till the specs come out... there'd be little worse than buying the basic Alpha only to find three months later that it can't run XCOM 2. I don't think
that will be the case but it's something to keep in mind. If you can resist getting XCOM 2 on launch then it may be worth waiting until the first couple of dedicated PC reviews are in so the performance on different sorts of systems can be judged.
Overall the Alpha looks to be one of the better "Steam machines" (small form factor PC's designed to offer a console like user experience for PC gaming) both in terms of performance and price. The small size and Alienware label drive the price up compared to non-brand, full size PC's but not by a vast amount and while the specs for the entry level are slightly underwhelming (personally I'd like 8 gigs of RAM rather than 4) they're not deal breaking, especially if you are only really using it to game (a 500 gig hard drive is pretty small but it should be more than enough to hold a dozen or so games).
And here is my problem. I found the Alpha by doing a search but I don't even know what to search for to find a more powerful rig (of the off-the-shelf type) in a similar price point. When I do a search for pc gaming desktops, I get reviews for things that cost 7K (not including peripherals), and much of the review is so technical that I don't understand enough to be able to compare it with other rigs. Unless the computer is actually going to fly me to the moon, I'm not going to pay that much.
Oh, I absolutely appreciate that. I see the high end rig or component reviews as being roughly similar to car magazines or websites reviewing supercars; somewhat interesting to read but unlikely to be bought by any but the most rich and hardcore of enthusiasts. Likewise trying to work out what the hell the different components actually mean or do can be a minefield.
Do you have suggestions for something 550$ or less with an i5 comparable [tech object name], that I wouldn't have to build?
I'm in a slight bit of difficulty as I'm UK based and our prices are somewhat higher than in the US; for an obvious example the entry level Alpha model from Dell's website is $499 in the US... and £499 (roughly $780) in the UK. That means the custom build company I use and tend to recommend is going to look expensive in comparison.
A quick google suggests that this system
may fulfill your needs. If you ignore the vast, ugly and offputting list of options and just stick to the base model then the processor gives comparable (and often superior) performance to an i5, it's got twice as much RAM as the Alpha and twice as much hard disk space for $579. The only concern is the graphics card; the one that comes with it is very much the entry level of entry level cards and it's the area I'd look to spend some money; upgrading to the AMD Radeon R7 250 sets you back $50 and the AMD Radeon R7 260X is $80, both of which push the price up considerably. If your budget can stretch to around $630 then this appears to be a like-for-like better system
; same graphics card but an i5, twice as much ram and twice as much hard disk space.
Basically the issue is this; an i5 (or equivalent) tends to push the price up to around the $600-$650 range. To use another supplier as an example, this
computer is in your $550 price range and offers twice as much RAM and hard disk space as the Alpha but the AMD processor is basically the equivalent of an i3 for gaming (and it should be noted the graphics card is fairly poor). This computer
is largely like-for-like better than the Alpha (i5 instead of i3 and again twice as much RAM and hard disk space... although again the graphics card is pretty low end)... but it's $650.
Someone with more knowledge of the prices and best custom build companies in the US would likely be able to help you more however; they may be in a better place to suggest other options.