OK, so here's an attempt at maybe not talking you out of it but querying your points:
Here's why:
a) They are quite cheap to buy (certainly cheaper than most high performance SEPs)
That's probably a false economy - you will also get less for it when you sell it. The impact of a lower purchase price on running costs is limited to the 'opportunity cost' of having your capital tied to the asset. In today's low-interest environment, that is not a lot. Of course, a more expensive aircraft may mean that you cannot afford it, but over the long run, running costs trump capital outlay quite quickly. Especially on twins
b) There are plenty out there and it is still in production, parts & maintenance should be widely available (unlike with lots of other vintage AVGAS twins)
This is a good thing - although Step Turn believes otherwise and it is worth doing a bit of research on your actual chosen model.
c) In the end it is a Piper Arrow with two standard engines... how bad can the maintenance bill really be?!
It will be
at least twice as much as an Arrow. Also keep in mind that that can translate to twice the downtime when it is stood in the hangar and you are unable to use it...
d) It has a second engine!! (At least once you are a few feet in the air that's a nice thing to have!)
Lots of truisms apply here - hours of fun to be had reading pasts threads on that subject. A second engine gives you some additional options in the case of some issues you may encounter. It also opens up the door for a whole host of new failure modes and does not remove all risk...
e) I love flying at night but hate doing it in a SEP (unless it had a chute)
So how much night flying have you actually done - you love night flying but hate doing it in the aircraft you are licensed to fly? Is this really a driver in your decision making?
f) It is not a turbocharged and/or pressurized high-end touring machine so bimbling around VFR is not prohibitive
I don't see what argument this makes
g) Relatively docile handling with one engine out
From what I read, that really depends on your definition of relative...
h) 90% of my flights are 1 or 2 POB so a 4-seater is more than enough
Then why not get a capable 2-seater?
i) Two well-leaned 4 cylinder engines burn only a little more fuel than a single 6 cylinder
Again, I'd research this and try to quantify what 'only a little' means. If you think that only a little is due to just having 8 cylinders instead of 6, you may need to rethink. Having had a quick look at a random PA-44 POH on the web, it seems you're likely to see around 20USgph per engine - in an SR22 the POH shows around 16 (per engine - but now there's only one of them...) as typical. Of course both POHs are probably way off, but for comparison...
j) stable platform for IFR flights (not IFR rated yet, but will change that within the next 24 month)
Like lots of decent SEPs, then.
k) Normally no glass cockpit but I am a bit old fashioned and actually like the steam gauges
Like lots of decent SEPs, then. NB - see below regarding need for an upgrade soon.
l) They are not unpopular for MEP training, so there is a realistic chance to find a buyer once you want to get rid of it again
Like lots of decent SEPs, then. As above, resale price is not really the big driver.
m) Oh did I mention I has a second engine!?
Err. yes, an MEP has M Es
Sure everything in aviation is a compromise so lets face it:
a) You have to keep your skills sharp when it comes to one engine out scenarios, but then that's just a good excuse to fly more often
Again, see past threads for hours of entertainment on this topic.
b) A SR22T / A36TC / TTX / Acclaim / you-name-it at FL200 will still cruise faster
There are always aircraft which go faster/higher/use less fuel/carry more weight/have a tailwheel...
c) If you brake it down to MPG there are certainly more efficient twins and singles out there, but then you saved a lot of cash purchasing it compared to any high-end sEP and saved a lot of money operating it compared to some other fast but highly-complex twin engined maintenance nightmare
As above, this really is false economy. As an estimate, a twin of that type flying 100 hours per year will cost its purchase price in running costs over one to two years.
Oh, as an aside (and this applies whether you buy ban SEP or an MEP), depending on where you fly, count on spending a large amount of cash on a nav/com/trx upgrade over the next years.
It would be interesting if those giving opinions about this aircraft told us if they had flown more than twenty hours in one or had owned/operated one at any time especially using the aircraft in the personal transport role.
None whatsoever, just applying common sense.
Has the OP ever flown a twin?
By all means, I think there's a lot of fun to had with cheap twins - but do your research and sums properly and know what you're letting yourself in for!
B.