Do you NEED a printer or WANT a printer?
If you are doing social housing and they have it in the contract to supply a read out then fine, but if not don't bother, I know some people say it proves that you did a test, but it doesn't, because you can reset the date on the machine and do a print out ( why would you unless you were dodgy, but in court it can be argued the read out is a bit of paper, no proof where the reading was taken or when) and I know some people say its better to give a print out as well, but think about you getting your car or van MOT'd, the guy comes up with the keys and says "it passed, hers your MOT and exhaust emission result" you have a quick look at the emission report but have no idea what it says can't understand it and don't care as he said it passed.
If money is no object but a full CPA kit from Kane, I use the 455, which has everything in it, the 455 might be superseded now, not sure, it has a 5 yr warranty if you get it serviced, fixed cost £85 per year and they are very robust, I had a testo again very good but service coasts are way too high
Before you buy any kit do at least a 5 yr total cost, purchase and 5 services, some machines have a small service then a big service, so you need to add up the full running cost plus initial purchase, then you get an idea of your total bill.
Choice of machine for a lot of people comes down to confidence in using it, so if you are shown how to use one machine you stick with it, but once you learn how to get the readings they are all pretty much the same, cost is king