am/fm tube tuners

Bryanhod, unless you have many good stations or you are super loaded, jumping on expensive FM-tuners is a money loosing investment. There are many good internet radiostations out there but not as good sound quality as the FM tuners. Most of the audiophiles I know don't listen to radio at all.
I have not heard the 109 yet but the 108 was quite impressive enough to most of the FM lovers.

You know S23chang you start off thinking maybe I can add an inexpensive tuner and then all hell breaks loose. Too much of a facination with great sound. There are jazz stations and classical stations that play music you just can find so i really want something that is good.

A McIntosh MR74 is also an excellent tuner that goes for around 500 and will probably appreciate as it is close in performance to the much more sought after units (mr78, mr71)

After a good station to listen to the next most important thing is not the tuner but having a good external FM antenna. If you have one of those almost any tuner in good repair will sound good.

I use an Onkyo T9 quartz locked tuner from around 1980. I paid 100 for it with a warranty from a local shop called The Sound Well. It works great; holds weak signals and sounds very good. I simply cannot justify the additional expense of a much more expensive tuner; most would be about 500 for a McTuner MR74. I'll send this tuner off for mods at some point.

I also listen to quite a bit of AM radio (Raiders, Talk Radio) at home so the AM feature is useful.

The "best" tuner depends very much on your location. If you are in a metro area, sensitivity does not matter, but multipath rejection is important. In all cases, a directional antenna on a rotator does more good than any tuner upgrade. With regard to audio quality, as opposed to the RF performance, this is not so hot for many FM broadcast stations, so is probably not of great concern.

You should try for an in home tryout. This is much more important for a tuner than for other components.