I've owned both and loved both. The evo had a much longer run than the TC but the TC design is more robust-chain tensioners aside...Long as you're not looking to make a fire breathing monster out of either of them, you will have many years of trouble-free service out of both. They are easily owner maintained. Personally, I like lower miles unless I have great maintenance records to follow the mileage. Too many folks treat their bikes like disposable toys to trust the word of a salesman.
I prefer the twin cam over the evo due to vibrations. The tc shakes at idle, the evo vibrates constantly which became fatiguing on longer trips. I have also been in your boat with finances. Get what makes you happy. You live once & it is only money. You aren't spending it on dope & whores so don't feel guilty. Two of my friends waited to buy Harleys. Both died within four months of buying them and starting to ride due to heart attacks & cancer. Live life to the fullest as long as you are taking care of your business.
Some people in this thread have mentioned that the Evo had a longer production run. But if you factor in production volume I think you will find that that there are more TC88s on the road than Evos. Not that it really matters. One of the problems I've had with metric bikes is obsolescence. After some time has passed, you can no longer get parts (other than salvage parts--and good luck there as well). This is not the case with Harleys. As far as dealers not working on older models, in my experience the independent repair shops are more skilled than the dealer mechanics, at least that is the case in the U.S. I don't believe parts availability will be a problem for either the Evo or the TC88.