Tamron 18-270mm ... any good?

I see that no-one has responded to you so far today.  I have not used this lens.  But I researched this a long time ago.  What I remember about this superzoom, is that the images were OK.  But for better images, not exceeding something like 8x zoom was generally better.  So I decided to initially use two cameras and lenses with them attached.  One camera had the 18-55mm lens and the other camera had the 55-250mm lens.  That combination is what I used to go from 18mm to 250mm.  It was a two lenses solution instead of a one lens solution.  But people will use that Tamron 18-270mm lens because the convenience factor is more important to them.

I haven't read recently anything about that lens.  I would suggest reading more up-to-date reviews about that lens before deciding.

If you are looking at super zooms I suggest checking out the Sigma versions.  I used a Sigma 18-250mm Macro for a number of years.  Its IQ was fairly good but no EF mount super zoom is going to be all that great.  The convenience is very addicting though.  IMO, the Sigma super zooms have better build quality than Tamron super zooms.  I think IQ is a little better too.

I'll mention a super zoom lens that is pricey but it is by far the best super zoom lens made, IMO.  It is the RF 24-240mm.  I have one I use on an R camera and the IQ, sharpness, AF speed etc. is outstanding.  Its IQ is very close to the EF 28-300L lens.  When paired with the RP camera it is a very formidable setup for around $1,100.  This might be more than you care to spend but will deliver very impressive results for a 10X lens solution.

I have this lens and use it with my Canon SL1.

I wanted to get a superzoom  for the SL1 but wanted to keep it light and small.  The whole rig is small and lightweight and is able to fit in a small camera holster.  The lens is pretty good for a superzoom as I've shot indoors in a car museum.  The VC works very well and I was able to get sharp images indoors without a flash at  ISO 800 to 1600.   It is the perfect zoom for going to the zoo having a relatively long range in a small physical size. Carrying a lightweight kit like this all day made it easy on the neck and shoulder.

Having a fairly small filter size (67mm)  makes it easy to carry a polarizer and an ND filter in the pocket of the holster zoom.

I will sometimes bring a pancake Canon 24mm STM lens and that fits it the holster as well.  This way I can have a prime with a f2.8 for low light shooting.

No, it won't match the IQ of zooms with shorter ratios or primes but it can hold it's own when it comes to image quality.  If you shoot a stop or two down from the maximum you can get impressive results.